Year	Percent
1970	43.75142
1971	40.94605
1972	38.08609
1973	30.63997
1974	39.45215
1975	34.84285
1976	8.75465
1977	33.15042
1978	13.33513
1979	22.4008
1980	31.02495
1981	45.59626
1982	55.88577
1983	59.6137
1984	76.47129
1985	92.11295
1986	96.40095
1987	152.43269
1988	161.77378
1989	148.19256
1990	125.13032
1991	157.22331
1992	135.33856
1993	117.53835
1994	144.73933
1995	143.98431
1996	108.04235
1997	118.95125
1998	119.8979
1999	130.09944
2000	124.13531
2001	93.60443
2002	105.03677
2003	92.31149
2004	89.26508
2005	71.0795
2006	28.09104
2007	31.4202
2008	26.62454
2009	33.18948
2010	31.47758
2011	29.05253
2012	30.76095
2013	28.165
2014	27.67305
2015	31.60197
2016	30.62165