Year	Percent
1987	40.15933
1988	41.91401
1989	42.02195
1990	39.84928
1991	38.39825
1992	38.34028
1994	43.52163
1995	44.03327
1996	44.56943
1997	43.97556
1998	44.29657
2000	48.10299
2001	48.70687
2002	49.25596
2003	51.57982
2012	71.01411