Year	Total
1971	967200000
1972	1159000000
1973	1547000000
1974	1704000000
1975	2026000000
1976	2390000000
1977	2910000000
1978	3914000000
1979	4981000000
1980	5318000000
1981	5936000000
1982	6600000000
1983	7744000000
1984	8759000000
1985	9634000000
1986	10300000000
1987	11460000000
1988	13210000000
1989	15180000000
1990	17740000000
1991	19490000000
1992	21800000000
1993	23920000000
1994	26560000000
1995	28310000000
1996	30650000000
1997	32520000000
1998	32920000000
1999	34590000000
2000	37110000000
2001	39220000000
2002	42290000000
2003	44580000000
2004	48620000000
2005	50880000000
2006	52550000000
2007	54200000000
2008	56240000000