Year Number 1970 145300 1971 151200 1972 159800 1973 173400 1974 201400 1975 215500 1976 252000 1977 274500 1978 295700 1979 314400 1980 330000 1981 341600 1982 324500 1983 352300 1984 349000 1985 344800 1986 340700 1987 334500 1988 355500 1989 356900 1990 354400 1991 319800 1992 370600 1993 390200 1994 405800 1995 388600 1996 408400 1997 407400 1998 402500 1999 441200 2000 470300 2001 470936 2002 473898 2003 493857 2004 553147 2005 431300 2006 471714 2007 516679 2008 504211 2009 811221 2010 1065038.0107150872 2011 1093318.5607948557 2012 1159025.9385851917 2013 1222183.5 2014 1289638.767440561 2015 1375862 2016 1476812 2017 1503553.38 2018 1539592.7535301668 2019 1599362.2719999999 2020 664879.575 2021 920600.238