Year	% of total
1990	50.60944758113908
1991	50.56734949203805
1992	50.852102037863446
1993	50.60036023064603
1994	50.86966225495208
1995	51.04751708733023
1996	50.6955225660266
1997	50.22378802382934
1998	50.30893049282474
1999	50.182967725876516
2000	49.67450492602586
2001	49.19508547822338
2002	49.10740038309499
2003	48.53019190595237
2004	48.37434370355053
2005	48.41893704461438
2006	47.756992063044436
2007	47.30453103334053
2008	46.876487738106036