Year	Total
1971	2094000000
1972	2282000000
1973	2517000000
1974	2751000000
1975	3072000000
1976	3561000000
1977	4105000000
1978	4865000000
1979	5544000000
1980	6352000000
1981	7025000000
1982	7486000000
1983	8096000000
1984	8086000000
1985	7795000000
1986	7730000000
1987	8501000000
1988	9655000000
1989	9689000000
1990	9502000000
1991	10670000000
1992	12120000000
1993	13450000000
1994	12750000000
1995	12390000000
1996	12790000000
1997	13520000000
1998	14410000000
1999	15020000000
2000	15180000000
2001	15960000000
2002	16600000000
2003	16620000000
2004	17000000000
2005	18680000000
2006	20530000000
2007	21560000000
2008	25620000000