Year	% of total
1990	41.9505708811826
1991	41.51539873385332
1992	41.25517311565261
1993	41.111886582220706
1994	41.28282091361274
1995	41.2157826465396
1996	40.86749400438093
1997	41.00006492692105
1998	41.421131699469875
1999	42.28053213355129
2000	42.70149489311784
2001	43.28718150220894
2002	43.6340637290284
2003	42.40054496185139
2004	43.48580067166524
2005	43.05401738875878
2006	43.640066434334145
2007	43.62150070129067
2008	42.66317245424446