Year	% of total
1990	65.62321078819592
1991	65.37436588263947
1992	64.75666769530332
1993	64.55716510041393
1994	63.7983668933975
1995	63.04955573970326
1996	62.33322657875646
1997	62.79007743392544
1998	65.2191192545111
1999	68.47915194616941
2000	68.13862052781586
2001	69.04405753317712
2002	69.283328066803
2003	67.49942302597925
2004	68.46753322487045
2005	67.43766992229217
2006	69.39604734063238
2007	70.50610769857971
2008	71.73284212493584