Year	% of total
1970	47.151540320400166
1971	47.490663659634706
1972	48.57931298001605
1973	46.27172611549918
1974	45.6398977834171
1975	46.35668545227415
1976	45.49264470397335
1977	47.245633374385065
1978	44.616008407200944
1979	44.52860826474559
1980	45.2136499494405
1981	45.13044839931272
1982	46.5450216761706
1983	47.484065995230814
1984	48.26529409709687
1985	47.99642065270803
1986	54.0842091179717
1987	53.27072964126022
1988	57.90327597694835
1989	59.040030614145365
1990	61.34663341645885
1991	61.12956810631229
1992	61.67883211678832
1993	64.63414634146342
1994	54.44839857651246
1995	50.171821305841924
1996	48.40764331210191
1997	48.84488448844885
1998	51.9434628975265
1999	53.01724137931034
2000	49.6124031007752
2001	47.482014388489205
2002	47.46376811594203
2003	44.642857142857146
2004	43.666666666666664
2005	42.508710801393725
2006	38.9937106918239
2007	40.74074074074074
2008	41.95804195804196