Year	Total
1975	1517000000
1976	1593000000
1977	1776000000
1978	2544000000
1979	2462000000
1980	2938000000
1981	3425000000
1982	3590000000
1983	3992000000
1984	4199000000
1985	4483000000
1986	3537000000
1987	4703000000
1988	5106000000
1989	5162000000
1990	5610000000
1991	6250000000
1992	6054000000
1993	6369000000
1994	7283000000
1995	8224000000
1996	9152000000
1997	10480000000
1998	11940000000
1999	11880000000
2000	12900000000
2001	13550000000
2002	13720000000
2003	15360000000
2004	15920000000
2005	16030000000
2006	15830000000
2007	16380000000
2008	16650000000