Year	% of total
1990	7.486322089574972
1991	7.702327433573906
1992	7.681343657468703
1993	7.886330150156608
1994	7.927010746034138
1995	8.303938760485654
1996	8.476641319870822
1997	8.55080071718221
1998	9.045551805240711
1999	9.30260279001045
2000	9.295178256472372
2001	9.39302055965157
2002	9.18703973312602
2003	9.467558963418345
2004	9.560253357391739
2005	9.672924397353006
2006	9.963548855900271
2007	10.030406775710366
2008	10.225130945796927