Year	Percent
1975	63.23174
1976	53.82403
1977	59.2037
1978	66.2097
1979	77.13177
1980	67.27793
1981	83.51744
1982	94.13654
1983	93.20796
1984	60.75109
1985	80.10139
1986	125.02061
1987	129.20769
1988	106.64039
1989	112.82783
1990	118.44642
1991	149.02339
1992	121.92613
1993	161.63944
1994	185.70223
1995	178.43102
1996	163.65723
1997	150.76064
1998	122.32723
1999	190.10144
2000	149.82254
2001	121.27511
2002	157.2366
2003	148.78059
2004	193.29293
2005	213.18248
2006	261.6642
2007	276.95402
2008	168.12957
2009	268.83539
2010	246.47262
2011	189.27284
2012	229.03061
2013	257.01651
2014	266.14948
2015	231.61791
2016	321.64988
2017	352.29223