Year	% of total
1990	49.903683764555325
1991	49.35234437488347
1992	48.69671833552586
1993	47.57515354332847
1994	47.47232489213104
1995	47.11773142223539
1996	47.27284056832459
1997	47.76947576679131
1998	48.12122575953654
1999	48.39001561804208
2000	48.90450785666652
2001	48.800199893042915
2002	49.321879491147286
2003	49.15556710082695
2004	50.06619080028676
2005	50.52477090914612
2006	51.01000195672371
2007	51.83740502560074
2008	52.161618637878306