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| Most popular ECO Codes | |||
| Year | ECO | Opening name | Number of games |
| 1620 | C53 | Giuoco Piano | 17 |
| 1620 | C33 | Kings gambit accepted | 14 |
| 1620 | C23 | Bishops opening | 12 |
| 1620 | C40 | Kings knight opening | 9 |
| 1620 | C54 | Giuoco Piano | 9 |
| 1620 | C37 | KGA: Kings knights gambit | 6 |
| 1620 | C41 | Philidors defence | 6 |
| 1620 | C50 | Kings pawn game | 6 |
| 1620 | B20 | Sicilian defence | 5 |
| 1620 | C34 | Kings knights gambit | 4 |
| 1620 | B00 | Kings pawn opening | 4 |
| 1620 | C02 | French: advance variation | 3 |
| 1620 | C01 | French: exchange variation | 3 |
| 1620 | C30 | Kings gambit | 3 |
| 1620 | B21 | Sicilian: Grand Prix attack | 3 |
| 1620 | C57 | Two knights defence | 3 |
| 1620 | C38 | Kings knights gambit | 2 |
| 1620 | D20 | Queens gambit accepted | 2 |
| 1620 | C39 | Kings knights gambit | 1 |
| 1620 | C31 | KGD: Falkbeer counter-gambit | 1 |
| Year | Number of games | World championship |
| 1475 | 1 | |
| 1485 | 1 | |
| 1497 | 2 | |
| 1500 | 1 | |
| 1512 | 1 | |
| 1515 | 1 | |
| 1560 | 3 | |
| 1575 | 7 | |
| 1580 | 1 | |
| 1590 | 10 | |
| 1600 | 1 | |
| 1610 | 2 | |
| 1619 | 2 | |
| 1620 | 92 | |
| 1625 | 2 | |
| 1634 | 2 | |
| 1680 | 21 | |
| 1700 | 2 | |
| 1723 | 2 | |
| 1737 | 6 | |
| 1749 | 3 | |
| 1750 | 4 | |
| 1755 | 1 | |
| 1765 | 2 | |
| 1769 | 3 | |
| 1770 | 2 | |
| 1780 | 1 | |
| 1783 | 4 | |
| 1787 | 2 | |
| 1788 | 22 | |
| 1789 | 5 | |
| 1790 | 25 | |
| 1792 | 2 | |
| 1794 | 5 | |
| 1795 | 18 | |
| 1796 | 4 | |
| 1797 | 1 | |
| 1798 | 11 | |
| 1800 | 1 | |
| 1801 | 21 | |
| 1802 | 3 | |
| 1803 | 1 | |
| 1804 | 6 | |
| 1806 | 1 | |
| 1809 | 3 | |
| 1810 | 7 | |
| 1813 | 4 | |
| 1814 | 1 | |
| 1815 | 2 | |
| 1816 | 4 | |
| 1817 | 3 | |
| 1818 | 15 | |
| 1819 | 11 | |
| 1820 | 14 | |
| 1821 | 6 | |
| 1822 | 5 | |
| 1824 | 7 | |
| 1825 | 5 | |
| 1827 | 4 | |
| 1828 | 3 | |
| 1829 | 3 | |
| 1830 | 17 | |
| 1831 | 7 | |
| 1832 | 3 | |
| 1833 | 3 | |
| 1834 | 157 | Unofficial - London: Labourdonnais - McDonnell |
| 1835 | 3 | |
| 1836 | 20 | |
| 1837 | 35 | |
| 1838 | 18 | |
| 1839 | 52 | |
| 1840 | 23 | |
| 1841 | 68 | |
| 1842 | 129 | |
| 1843 | 71 | Unofficial - Paris/London: Staunton - Saint-Amant |
| 1844 | 23 | |
| 1845 | 52 | |
| 1846 | 107 | Unofficial - London: Staunton - Horwitz |
| 1847 | 36 | |
| 1848 | 41 | |
| 1849 | 112 | |
| 1850 | 97 | |
| 1851 | 417 | Unofficial - London: Tournament (Anderssen 1st) |
| 1852 | 113 | |
| 1853 | 176 | |
| 1854 | 149 | |
| 1855 | 314 | |
| 1856 | 275 | |
| 1857 | 279 | |
| 1858 | 289 | Unofficial - Paris/London: Morphy matches |
| 1859 | 213 | Unofficial - Paris/London: Morphy matches |
| 1860 | 174 | |
| 1861 | 199 | Unofficial - London: Anderssen - Kolisch |
| 1862 | 352 | Unofficial -London: Anderssen - Paulsen |
| 1863 | 113 | |
| 1864 | 192 | |
| 1865 | 191 | |
| 1866 | 231 | London: Steinitz - Anderssen |
| 1867 | 276 | |
| 1868 | 144 | |
| 1869 | 115 | |
| 1870 | 195 | |
| 1871 | 186 | |
| 1872 | 121 | |
| 1873 | 352 | |
| 1874 | 131 | |
| 1875 | 107 | |
| 1876 | 196 | |
| 1877 | 127 | |
| 1878 | 269 | |
| 1879 | 172 | |
| 1880 | 392 | |
| 1881 | 269 | |
| 1882 | 425 | |
| 1883 | 633 | Unofficial - London: Tournament (Zukertort 1st) |
| 1884 | 96 | |
| 1885 | 259 | |
| 1886 | 136 | USA: Steinitz - Zukertort (First 'Official' World Championship match) |
| 1887 | 427 | |
| 1888 | 172 | |
| 1889 | 969 | Havana: Steinitz - Chigorin |
| 1890 | 432 | New York: Steinitz - Gunsberg |
| 1891 | 161 | |
| 1892 | 426 | Havana: Steinitz - Chigorin |
| 1893 | 450 | |
| 1894 | 437 | USA/Canada: Lasker - Steinitz |
| 1895 | 581 | |
| 1896 | 580 | Moscow: Lasker - Steinitz |
| 1897 | 480 | |
| 1898 | 641 | |
| 1899 | 655 | |
| 1900 | 720 | |
| 1901 | 473 | |
| 1902 | 703 | |
| 1903 | 739 | |
| 1904 | 873 | |
| 1905 | 1199 | |
| 1906 | 599 | |
| 1907 | 1029 | USA: Lasker - Marshall |
| 1908 | 958 | Germany: Lasker - Tarrasch |
| 1909 | 785 | Paris: (Lasker - Janowski) |
| 1910 | 529 | Berlin: Lasker - Janowski and Germany Lasker - Schlechter |
| 1911 | 990 | |
| 1912 | 1052 | |
| 1913 | 744 | |
| 1914 | 616 | |
| 1915 | 300 | |
| 1916 | 518 | |
| 1917 | 116 | |
| 1918 | 248 | |
| 1919 | 446 | |
| 1920 | 850 | |
| 1921 | 789 | Havana: Capablanca - Lasker |
| 1922 | 1138 | |
| 1923 | 1136 | |
| 1924 | 1281 | |
| 1925 | 1372 | |
| 1926 | 1192 | |
| 1927 | 1210 | Buenos Aires: Alekhine - Capablanca |
| 1928 | 1368 | |
| 1929 | 1126 | Europe: Alekhine - Bogoljubov |
| 1930 | 1304 | |
| 1931 | 1679 | |
| 1932 | 1165 | |
| 1933 | 1366 | |
| 1934 | 1276 | Germany: Alekhine - Bogoljubov |
| 1935 | 1756 | Netherlands: Euwe - Alekhine |
| 1936 | 2269 | |
| 1937 | 1933 | Netherlands: Alekhine - Euwe |
| 1938 | 1698 | |
| 1939 | 2047 | |
| 1940 | 940 | |
| 1941 | 1043 | |
| 1942 | 791 | |
| 1943 | 758 | |
| 1944 | 622 | |
| 1945 | 1481 | |
| 1946 | 2691 | Alekhine died with the title of World champion |
| 1947 | 2378 | |
| 1948 | 2247 | Fide organised match tournament between five of the world's strongest players: Mikhail Botvinnik, Vasily Smyslov, Paul Keres, Samuel Reshevsky, and Max Euwe. Reuben Fine was also invited but could not attend due to degree commitments. Note Max Euwe was a gentleman to accept this match tournament instead of taking the title of World champion by default. |
| 1949 | 2368 | |
| 1950 | 3994 | |
| 1951 | 4628 | Botvinnik - Bronstein |
| 1952 | 4915 | |
| 1953 | 3517 | |
| 1954 | 5474 | Botvinnik - Smyslov |
| 1955 | 5767 | |
| 1956 | 5068 | |
| 1957 | 5752 | Smyslov - Botvinnik |
| 1958 | 5581 | |
| 1959 | 5545 | |
| 1960 | 3835 | Tal - Botvinnik |
| 1961 | 7612 | |
| 1962 | 5410 | |
| 1963 | 4168 | Petrosian - Botvinnik |
| 1964 | 4408 | |
| 1965 | 4784 | |
| 1966 | 5601 | Petrosian - Spassky |
| 1967 | 5487 | |
| 1968 | 12149 | |
| 1969 | 10416 | Spassky - Petrosian |
| 1970 | 11502 | |
| 1971 | 9163 | |
| 1972 | 14627 | Fischer - Spassky |
| 1973 | 12298 | |
| 1974 | 12676 | |
| 1975 | 7227 | Karpov-Fischer (by forfeit) |
| 1976 | 6693 | |
| 1977 | 7911 | |
| 1978 | 8758 | Karpov - Korchnoi |
| 1979 | 8472 | |
| 1980 | 15499 | |
| 1981 | 18598 | Karpov - Korchnoi |
| 1982 | 11050 | Las Palmas: Karpov - Kasparov Part I |
| 1983 | 10039 | Moscow: Kasparov - Karpov Part II |
| 1984 | 14480 | Toluca: Kasparov - Karpov Part III |
| 1985 | 12282 | |
| 1986 | 26919 | |
| 1987 | 34877 | Biel: Kasparov - Karpov |
| 1988 | 46580 | |
| 1989 | 29018 | |
| 1990 | 28720 | Subotica: Kasparov - Karpov |
| 1991 | 29859 | |
| 1992 | 96656 | |
| 1993 | 40914 | The start of chaos!: The 'PCA' (Professional Chess Association) was created by Kasparov and Short |
| 1994 | 39590 | |
| 1995 | 45637 | Groningen: Kasparov - Anand (PCA) |
| 1996 | 57214 | Biel: Karpov - Kamsky (FIDE) |
| 1997 | 160200 | |
| 1998 | 68398 | Las Vegas: Karpov - Anand (FIDE) |
| 1999 | 63937 | Las Vegas: Fide Knockout tournament: 1st - Khalifman (FIDE) |
| 2000 | 77148 | |
| 2001 | 87702 | |
| 2002 | 151003 | Moscow: Fide tournament: 1st - Ponomariov |
| 2003 | 83440 | |
| 2004 | 85131 | Tripoli: 1st: Kasimdzhanov |
| 2005 | 91078 | San Luis: 1st: Topalov |
| 2006 | 93837 | |
| 2007 | 96182 | |
| 2008 | 121599 | |
| 2009 | 109277 | |
| 2010 | 130348 | |
| 2011 | 64362 | |
| 2012 | 41634 | |
| 2013 | 129492 | |
| 2014 | 139610 | |
| 2015 | 142898 | |
| 2016 | 48583 | |
| 2017 | 173392 | |
| 2018 | 60259 | |
| 2019 | 481 |