Year Number 1970 67700 1971 67600 1972 67600 1973 72400 1974 69700 1975 79700 1976 88300 1977 100800 1978 105700 1979 112800 1980 116600 1981 122800 1982 116700 1983 121300 1984 119100 1985 122300 1986 109400 1987 103600 1988 98300 1989 91400 1990 85000 1991 94700 1992 81900 1993 68900 1994 70100 1995 66400 1996 62100 1997 78000 1998 78400 1999 69400 2000 71122 2001 60104 2002 52346 2003 49482 2004 56301 2010 120773.31996851471 2011 138169.49789716364 2012 146632.96028827317 2013 155038 2014 145526.8233093528 2015 164614 2016 157788 2017 151203 2018 157126.726523888 2019 158874.79 2020 92611.349 2021 134532.013