Year Number 1970 8067885 1971 8612076 1972 9262602 1973 9840391 1974 10157006 1975 10551088 1976 10982062 1977 12624571 1978 14892927 1979 17074654 1980 18391170 1981 20071448 1982 22057148 1983 22904798 1984 23426414 1985 23548970 1986 22440532 1987 22695066 1988 22848066 1989 23290800 1990 24444250 1991 25111928 1992 26400424 1993 27898618 1994 28698194 1995 28819438 1996 27612626 1997 29679122 1998 31629938 1999 33662824 2000 35906812 2001 37072416 2002 38849328 2003 40215756 2004 42229688 2005 43821784 2006 45446732 2007 45392364 2008 45481352 2009 47810924 2010 49762224 2011 53312656 2012 55914780 2013 58310760 2014 59074840 2015 60213272 2016 61047148 2017 62918760 2018 64573820 2019 66877088 2020 68800760 2021 70216776 2022 71722488