Year Number 1970 1413537.25 1971 1658519.625 1972 1851446.875 1973 2200291 1974 2262812.5 1975 2378103.25 1976 2723175.5 1977 3409547.75 1978 3934800.5 1979 4012960.75 1980 3988897.25 1981 4018320.5 1982 3888026 1983 3838114 1984 3859837.5 1985 3996860 1986 4233162 1987 4516205 1988 4748619.5 1989 4936229 1990 5089589.5 1991 5159761 1992 5217611 1993 5307354 1994 5395607 1995 5544621 1996 5807205 1997 6010428.5 1998 6170351.5 1999 6402393.5 2000 6583859 2001 6435498.5 2002 6747693 2003 7122247.5 2004 7510566.5 2005 7868900 2006 8064396 2007 8632129 2008 8862080 2009 8925042 2010 9045302 2011 8836979 2012 8847725 2013 8704468 2014 8788426 2015 9002232 2016 9130529 2017 9159374 2018 9358110 2019 9500274 2020 9669353 2021 9949400 2022 10191659