Year Total 1970 6939000 1971 6725000 1972 6684000 1973 8234000 1974 8702000 1975 8464000 1976 10492000 1977 11453000 1978 11557000 1979 12944000 1980 13325000 1981 13397000 1982 14295000 1983 14076000 1984 15570000 1985 15593000 1986 17167000 1987 16728000 1988 17125000 1989 17584000 1990 19769000 1991 19712000 1992 19456000 1993 20996000 1994 22208000 1995 24751000 1996 26758000 1997 27747000 1998 29102000 1999 24669000 2000 25132000 2001 26634000 2002 25574000 2003 22702000 2004 25565000 2005 24677000 2006 28334000 2007 32596000 2008 29487000 2009 27912000 2010 27557000 2011 24841000 2012 26529000 2013 25592000 2014 25774000 2015 29181000 2016 30865000