Year Total 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 237010 1982 1208000 1983 1422100 1984 2122900 1985 2790600 1986 3219200 1987 4497700 1988 5330900 1989 5325600 1990 5803800 1991 7192700 1992 7673600 1993 8636800 1994 9547400 1995 10108000 1996 11686000 1997 14385000 1998 15618000 1999 17108000 2000 17966000 2001 17476000 2002 18267000 2003 19104000 2004 19903000 2005 21081000 2006 21643000 2007 23133000 2008 25622000 2009 27502000 2010 32248000 2011 32901000 2012 36855000 2013 37196000 2014 37463000 2015 35412000 2016 34734000