Year	% of total
1990	40.64077759941269
1991	43.711490953754634
1992	43.27902329482032
1993	44.171146855064016
1994	44.73465747229394
1995	45.81110643105725
1996	46.32055033965185
1997	45.22715647572437
1998	44.247948954323945
1999	43.428694158689815
2000	43.88284030134166
2001	44.27138127128187
2002	44.61631576966988
2003	46.36203057400918
2004	45.78257267235008
2005	46.393192426529204
2006	46.59559032649091
2007	46.230631085322486
2008	46.30164731899686