Year	% of total
1990	32.97633912623887
1991	32.7261100777093
1992	32.293525700933074
1993	33.12680325619807
1994	32.73818022835032
1995	33.64718278374617
1996	34.970937785614325
1997	35.85365382651378
1998	36.73229050043429
1999	37.81331867438637
2000	40.0011390657029
2001	40.806100466242874
2002	40.95956555066483
2003	40.94358161085133
2004	41.011936455694126
2005	40.79616166417815
2006	40.5949545563709
2007	39.36827363364359
2008	39.38176511655047