Year	Percent
1970	33.35991
1971	59.6508
1972	60.71399
1973	43.18602
1974	37.16812
1975	39.40486
1976	35.64595
1977	42.05359
1978	30.37003
1979	27.16843
1980	28.91961
1981	49.13306
1982	72.36046
1983	77.18221
1984	82.10664
1985	90.46954
1986	77.08872
1987	75.85765
1988	64.00379
1989	67.8738
1990	83.77329
1991	75.72319
1992	95.21828
1993	71.97791
1994	54.78012
1995	57.33556
1996	53.41105
1997	56.13674
1998	76.96871
1999	83.25222
2000	70.39739
2001	72.30645
2002	66.94063
2003	59.5362
2004	49.72702
2005	41.32157
2006	35.54315
2007	24.4117
2008	18.11142
2009	22.48153
2010	65.62061
2011	102.12415
2012	101.77567
2013	146.3296
2014	123.60818