Year	Total
1971	2828000000
1972	3228000000
1973	3648000000
1974	4114000000
1975	4589000000
1976	5193000000
1977	5534000000
1978	5837000000
1979	6510000000
1980	6845000000
1981	7001000000
1982	8001000000
1983	8502000000
1984	9446000000
1985	9554000000
1986	8687000000
1987	9447000000
1988	9937000000
1989	10180000000
1990	10480000000
1991	10410000000
1992	10000000000
1993	10020000000
1994	9808000000
1995	10960000000
1996	11490000000
1997	9884000000
1998	10540000000
1999	10120000000
2000	9860000000
2001	9753000000
2002	9308000000
2003	9313000000
2004	8772000000
2005	9048000000
2006	9307000000
2007	9378000000
2008	10030000000