Year	Percent
1971	55.80255
1972	51.57508
1973	46.43515
1974	44.74092
1975	53.49569
1976	75.55791
1977	62.86929
1978	68.66979
1979	67.51269
1980	76.77165
1981	88.55432
1982	87.88103
1983	93.47462
1984	95.7584
1985	94.98429
1986	93.7154
1987	92.56629
1992	55.21065
1994	80.40799
1995	79.62417
1996	100.6355
1997	96.95303
1999	93.95263
2000	97.62289
2001	89.11089
2002	96.3306
2003	105.08823
2004	106.83215
2005	113.84058
2007	107.64782
2010	96.50132
2011	98.82336
2012	98.22785
2013	101.78503
2016	104.29157