Year	Percent
1974	44.66354
1975	41.74547
1976	52.4433
1977	59.05461
1978	63.5429
1979	67.20304
1980	67.5787
1981	72.22473
1982	84.07044
1983	82.30518
1984	77.42464
1985	74.4998
1986	73.44413
1987	73.2106
1988	72.58076
1989	81.43763
1990	91.55055
1991	98.03142
1992	95.57763
1993	92.27754
1994	90.34715
1995	88.42571
1996	84.26815
1997	86.1694
1998	83.29478
1999	81.27865
2000	78.24046
2001	74.53136
2002	80.97098
2007	96.39903
2009	83.55468
2010	81.89901
2011	86.83659
2012	95.38652
2013	95.71464
2014	98.67779
2015	103.47819