Year	Total
1971	983200000
1972	1218000000
1973	1423000000
1974	1620000000
1975	2034000000
1976	2620000000
1977	3239000000
1978	3798000000
1979	4703000000
1980	5480000000
1981	5810000000
1982	7351000000
1983	8859000000
1984	10070000000
1985	11320000000
1986	12420000000
1987	13670000000
1988	14000000000
1989	15790000000
1990	17350000000
1991	19130000000
1992	19510000000
1993	22150000000
1994	22480000000
1995	23380000000
1996	24000000000
1997	26530000000
1998	28690000000
1999	29760000000
2000	31270000000
2001	32900000000
2002	34950000000
2003	37970000000
2004	40570000000
2005	44200000000
2006	48090000000
2007	50790000000
2008	52910000000