Year Number 1970 2881100 1971 3012300 1972 3275800 1973 3682400 1974 3627100 1975 3827700 1976 4080900 1977 4452000 1978 4718300 1979 4918900 1980 4983800 1981 5058000 1982 5201900 1983 5278900 1984 5654900 1985 6027700 1986 6382000 1987 7403400 1988 7860100 1989 8253400 1990 8559400 1991 8893200 1992 10087800 1993 11774600 1994 12894800 1995 16377900 1996 17114300 1997 17889900 1998 18675500 1999 19741200 2000 20898713 2001 20072980 2002 22931166 2003 23454932 2004 25595676 2005 26132696 2006 27454451 2007 28857440 2008 29601230 2009 29108547 2010 26979676.6296817 2011 29959476.4043769 2012 31672223.9759589 2013 33455251 2014 33956338 2015 35687843 2016 40078714 2017 42763443 2018 44417573.579144 2019 46358457.951 2020 14748517.334 2021 19349165.526