Year	Percent
1972	51.89072
1973	53.08979
1974	50.91999
1975	49.28826
1976	48.74035
1977	53.284
1978	56.06429
1981	65.4278
1982	69.99298
1983	75.19183
1984	84.66342
1985	94.15121
1986	96.55025
1987	95.82461
1988	95.9828
1989	96.18225
1990	93.32744
1991	90.27253
1992	88.71572
1993	92.1608
1994	94.60677
1995	94.53097
1996	93.52371
1997	94.15936
2001	93.75859
2002	95.02653
2003	95.6103
2004	95.51278
2005	94.10486
2006	92.36255
2007	95.98368
2008	96.08751
2009	98.4924
2010	101.76147
2011	100.19998
2012	105.25459
2013	102.32989
2014	103.8482
2015	102.16755
2016	98.81906