Year	% of total
1990	43.11042170447287
1991	43.787257786006954
1992	44.09594204215124
1993	44.262824999376626
1994	44.85650390603199
1995	45.35555860401165
1996	45.09973292168634
1997	43.97122872489184
1998	44.15906383915833
1999	43.80510097110754
2000	43.45714695794495
2001	42.65230916900646
2002	42.474808100396345
2003	41.576704456296085
2004	41.590049042482114
2005	41.496319208459866
2006	40.26609180284389
2007	39.03624242725267
2008	38.26057992315698