Year Number 1970 216500 1971 221500 1972 213900 1973 227500 1974 224300 1975 242800 1976 261600 1977 233100 1978 239900 1979 249000 1980 264900 1981 272400 1982 269100 1983 269100 1984 272500 1985 267000 1986 262200 1987 265400 1988 274800 1989 268100 1990 272700 1991 265700 1992 255800 1993 243600 1994 246900 1995 241900 1996 256800 1997 236100 1998 248900 1999 224800 2000 226175 2001 223542 2002 214168 2003 217640 2004 251709 2005 250009 2006 250482 2007 286183 2008 254859 2009 271231 2010 423255.5728528625 2011 482532.68656345614 2012 474712.1502561618 2013 537330.215238617 2014 592719.1510407926 2015 577707 2016 598997 2017 683401 2018 710450.7180198526 2019 664891.3 2020 354727.93539999996 2021 425094.0640000001