Year Number 1970 282300 1971 268200 1972 266300 1973 330000 1974 456500 1975 414100 1976 427200 1977 555000 1978 659000 1979 830200 1980 874300 1981 1017000 1982 1020700 1983 957300 1984 1038500 1985 1116100 1986 1150600 1987 1231400 1988 1176400 1989 1316300 1990 1363100 1991 910700 1992 1029100 1993 1216900 1994 1325400 1995 1310900 1996 1563400 1997 1634700 1998 1749200 1999 1943500 2000 2197521 2001 2023385 2002 2098760 2003 2260849 2004 2546234 2005 2735214 2006 2591666 2007 3133574 2008 3111575 2009 2952885 2010 12477063.1762511 2011 13729553.5346856 2012 12289555.0764284 2013 13926540 2014 16482060 2015 20043787 2016 21399963 2017 26066294 2018 31226848 2019 39803373 2020 14597294 2021 20127200