Year	Percent
1975	18.49046
1976	18.74267
1977	17.95773
1978	17.27176
1979	16.46082
1980	15.23883
1981	13.48295
1982	16.43438
1983	22.27356
1984	24.93424
1985	41.80169
1986	42.21599
1987	36.00609
1988	41.80685
1989	60.56538
1990	38.12847
1991	52.30003
1992	47.64991
1993	52.07292
1994	59.84638
1995	64.1955
1996	84.21673
1997	113.6904
1998	139.47179
1999	157.03487
2000	155.14657
2001	117.92171
2002	86.22572
2003	85.44826
2004	82.80348
2005	87.3701
2006	107.2791
2007	113.90699
2008	41.51988
2009	65.17939
2010	79.04198
2011	66.53222
2012	78.51061
2013	94.36473
2014	89.42044
2015	96.10635
2016	103.66648
2017	133.15239