Year Number 1974 305900 1975 335000 1976 352000 1977 355500 1978 364500 1979 410900 1980 420500 1981 460300 1982 478800 1983 489500 1984 591400 1985 604300 1986 637600 1987 699800 1988 765400 1989 740800 1990 804100 1991 823400 1992 889900 1993 910000 1994 1039100 1995 1138400 1996 1304200 1997 1223700 1998 1241700 1999 1149800 2000 1215806 2001 1522837 2002 1615064 2003 1586155 2004 2067761 2005 2219532 2006 2454357 2007 2702754 2008 2798473 2009 3092984 2010 3844391.026672279 2011 4196284.463181262 2012 4537127.000819762 2013 4868207.317995496 2014 5435979.691759948 2015 5872462 2016 6431220 2017 6919472.67 2018 7387203.841489686 2019 7629160 2020 4901478.069 2021 4732454.516