Year Number 1970 23500 1971 24000 1972 34200 1973 42500 1974 64800 1975 74100 1976 91600 1977 105500 1978 115300 1979 120400 1980 124800 1981 142600 1982 145300 1983 143400 1984 183000 1985 185800 1986 181500 1987 190600 1988 206100 1989 193200 1990 205400 1991 215700 1992 236900 1993 227200 1994 230500 1995 262200 1996 311200 1997 194700 1998 196700 1999 135000 2000 159027 2001 164651 2002 152278 2003 155609 2004 318488 2005 320724 2006 357414 2007 357789 2008 345240 2009 330112 2010 520932.081983182 2011 599692.276092406 2012 641182.300723356 2013 576000 2014 675005.895378656 2015 682389 2016 823735 2017 892801 2018 959307.381 2019 808265 2020 425057.604 2021 348232