Year Number 1970 5689700 1971 5878600 1972 5692700 1973 7016200 1974 7448000 1975 8641400 1976 10454700 1977 10949400 1978 12226000 1979 13405100 1980 15052000 1981 16345900 1982 16812500 1983 17321300 1984 17936400 1985 18469200 1986 18380600 1987 18304400 1988 19517000 1989 19165800 1990 20082400 1991 19161600 1992 23666100 1993 22612600 1994 22954600 1995 22288600 1996 21922600 1997 22744600 1998 22961000 1999 23392800 2000 23621423 2001 23699857 2002 21700384 2003 22216651 2004 25905542 2005 28043085 2006 30339043 2007 31490994 2008 31956149 2009 31678543 2010 44610898.77558336 2011 52675053.86677591 2012 54667963.651755035 2013 56037107.39122866 2014 58618240.98738684 2015 60040021 2016 62736598 2017 67552489.63031113 2018 77987583.39579992 2019 76480055.15019548 2020 32754952.523000002 2021 40880095.111999996