Year Number 1971 3800637.25 1972 3967168 1973 4134314.5 1974 4270498 1975 4338489.5 1976 4452149 1977 4637707.5 1978 4746800 1979 4768002 1980 4763980.5 1981 4811217.5 1982 4838313 1983 4947383.5 1984 5059470 1985 5262886.5 1986 5480455.5 1987 5693264.5 1988 5876315.5 1989 6020127.5 1990 6236688.5 1991 6417097.5 1992 6543491.5 1993 6690109.5 1994 6848996 1995 7049218 1996 7381662 1997 7654222 1998 7982113 1999 8296564 2000 8543095 2001 8556360 2002 9118824 2003 9500984 2004 9672755 2005 10018266 2006 9912246 2007 10393119 2008 10813792 2009 11087130 2010 11361810 2011 11548302 2012 11631492 2013 11586517 2014 11813512 2015 11994207 2016 12413998 2017 12715961 2018 13316618 2019 13929802 2020 14059430 2021 14820690 2022 15142769