Year Number 1970 2966600 1971 3107300 1972 3962000 1973 4589600 1974 5501500 1975 6522900 1976 7675700 1977 8238200 1978 9387700 1979 11381500 1980 12889800 1981 13853300 1982 12777300 1983 13923500 1984 14440200 1985 15364400 1986 13824500 1987 13504900 1988 11412300 1989 12689000 1990 14341300 1991 14901000 1992 15532200 1993 16484800 1994 18791400 1995 14968800 1996 14677700 1997 17266500 1998 17717400 1999 20561100 2000 20894205 2001 20172824 2002 19618662 2003 20661206 2004 21167881 2005 21857658 2006 21243010 2007 20952513 2008 18825976 2009 15728171 2010 31269061 2011 29538937 2012 32909408.724554 2013 35986501.817 2014 39570522 2015 46966763 2016 53313307 2017 58537832 2018 64569640 2019 69937838 2020 34133108 2021 54217876