Year	Total
1971	2513000000
1972	2888000000
1973	3184000000
1974	3258000000
1975	3718000000
1976	4256000000
1977	4802000000
1978	5378000000
1979	5379000000
1980	4890000000
1981	5133000000
1982	5051000000
1983	4995000000
1984	4785000000
1985	4815000000
1986	4993000000
1987	4808000000
1988	4483000000
1989	4297000000
1990	5355000000
1991	6748000000
1992	7597000000
1993	7024000000
1994	6647000000
1995	7117000000
1996	8123000000
1997	7947000000
1998	7918000000
1999	7884000000
2000	7653000000
2001	7725000000
2002	7772000000
2003	8244000000
2004	8044000000
2005	9236000000
2006	10000000000
2007	10390000000
2008	10400000000