Year	% of total
1990	89.30448934016442
1991	89.21260816078475
1992	90.12784925645707
1993	90.38628800683728
1994	90.92443283921556
1995	90.86858481260751
1996	90.48738553809955
1997	90.70653182303029
1998	90.14109487288977
1999	90.02105078200212
2000	89.8094470546386
2001	90.4560965324942
2002	90.18723385987383
2003	90.54166430719361
2004	90.01001195137417
2005	90.12663861105287
2006	89.6878015040659
2007	91.58303315001919
2008	91.12802644599546