Year	Percent
1970	14.23952
1971	16.12959
1972	16.8491
1973	17.59787
1974	16.49675
1975	18.03177
1976	22.46898
1977	42.70645
1978	37.91758
1979	39.67038
1980	45.79612
1981	38.51392
1982	40.76637
1983	41.65543
1984	38.46289
1985	40.04963
1986	39.46394
1987	37.7859
1988	38.65755
1989	49.11502
1990	61.48303
1991	58.03948
1992	69.90217
1993	60.50039
1994	107.89992
1995	133.49199
1996	121.14308
1997	116.46681
1998	123.55396
1999	107.45233
2000	121.47887
2001	109.08078
2002	100.77352
2003	87.1102
2004	70.61739
2005	47.82903
2006	19.31273
2007	15.49434
2008	12.38956
2009	13.92618
2010	13.65986
2011	11.77478
2012	14.36766
2013	16.98003
2014	16.2533
2015	23.63159
2016	30.45755