Year Number 1970 231600 1971 263100 1972 288500 1973 309200 1974 268700 1975 244300 1976 288000 1977 226100 1978 185800 1979 197400 1980 242900 1981 327600 1982 335300 1983 357500 1984 398800 1985 471200 1986 527500 1987 594100 1988 592600 1989 650800 1990 620300 1991 635600 1992 756400 1993 752000 1994 716400 1995 749900 1996 743000 1997 772300 1998 789900 1999 861400 2000 944595 2001 1027528 2002 1103184 2003 1117329 2004 1403293 2005 1667316 2006 1720306 2007 2290179 2008 2715017 2009 2914056 2010 3347022 2011 4440917.69083987 2012 5001121.86524561 2013 5671501 2014 6274582 2015 7074779 2016 8242114 2017 9566378 2018 11501244 2019 12631216 2020 4940183 2021 7065954