Year	Percent
1970	67.73568
1971	60.42947
1972	61.65177
1973	64.59335
1974	43.19902
1975	42.99572
1976	47.62496
1977	53.89767
1978	57.64598
1979	58.23646
1980	61.31347
1981	52.55944
1982	65.64949
1983	79.37721
1984	76.86418
1985	98.98688
1986	155.32188
1987	145.12882
1988	115.21339
1989	94.69763
1990	94.45577
1991	81.53383
1992	79.44951
1993	79.60704
1994	85.82045
1995	82.70504
1996	73.15237
1997	68.91711
1998	68.41683
1999	70.07362
2000	72.1878
2001	60.53157
2002	66.42577
2003	75.51264
2004	75.06416
2005	76.0812
2006	56.70427
2007	40.48324
2008	35.4461
2009	34.86593
2010	30.90694
2011	27.23831
2012	26.17769
2013	28.52465
2014	28.48946
2015	31.10402
2016	33.23331