Year	Percent
1971	199.66115
1972	154.61876
1973	183.30276
1974	229.41148
1975	212.83396
1976	133.74327
1977	64.16944
1978	52.33902
1979	2.3758
1980	4.14477
1981	2.24294
1982	4.04973
1983	1.37794
1984	0.98102
1985	0.70751
1986	5.02075
1987	7.88479
1988	5.85847
1989	6.09627
1990	15.00549
1991	17.64663
1992	23.31053
1993	24.82597
1994	23.1729
1995	24.91304
1996	22.59663
1997	22.61623
1998	23.14634
1999	23.58205
2000	22.32842
2001	21.43993
2002	18.31008
2003	9.2179
2004	12.30062
2005	14.73797
2006	16.8042
2007	20.39586
2008	29.0599
2009	42.4133
2010	36.62352
2011	43.50084
2012	43.07375
2013	38.04562
2014	30.39478
2015	21.07924
2016	17.33819