Year Total 1965 6936000 1966 7449000 1967 6060000 1968 6342000 1969 4680000 1970 6075000 1971 6264000 1972 7150000 1973 6722000 1974 7420000 1975 8218000 1976 9712000 1977 10366000 1978 10728000 1979 11763000 1980 13165000 1981 15151000 1982 17237000 1983 18990000 1984 20480000 1985 20803000 1986 20887000 1987 21707000 1988 22042000 1989 22911000 1990 23756000 1991 23369000 1992 22712000 1993 21611000 1994 21467000 1995 23280000 1996 24599000 1997 25962000 1998 27327000 1999 27812000 2000 27200000 2001 26082000 2002 25244000 2003 25920000 2004 26821000 2005 29818000 2006 28664000 2007 30559000 2008 32644000 2009 34392000 2010 36297000 2011 33697000 2012 35307000 2013 35758000 2014 38322000 2015 39625000 2016 40640000