Year	% of total
1990	50.266608596937154
1991	50.19224753477249
1992	50.41838405847242
1993	50.11344963315877
1994	50.349085603114105
1995	50.449585086196905
1996	50.022371058912285
1997	49.51905967028967
1998	49.58213838792782
1999	49.48889181005158
2000	48.960785463990916
2001	48.53572203804591
2002	48.52135646029921
2003	48.04801854500017
2004	47.92657602883715
2005	48.02429224027617
2006	47.413605047639884
2007	47.01195610216299
2008	46.62295035430969