Year Number 1970 457900 1971 494100 1972 545800 1973 592800 1974 611200 1975 590200 1976 601500 1977 645000 1978 688000 1979 694000 1980 541500 1981 522100 1982 574300 1983 601400 1984 710100 1985 778000 1986 808400 1987 910100 1988 844700 1989 735900 1990 759500 1991 772600 1992 767100 1993 801000 1994 1031200 1995 1097000 1996 1239100 1997 1334400 1998 1592700 1999 1350200 2000 1431818 2001 1357946 2002 1198920 2003 1133775 2004 1332811 2005 1528929 2006 1536157 2007 1720496 2008 1423422 2009 1364651 2010 1851416.84175507 2011 2150527 2012 2400160 2013 2602714 2014 3035882.7791066 2015 4134980 2016 5710834 2017 7242611 2018 7819740.55998243 2019 4656017 2020 903927 2021 1499034