Year	Percent
1971	82.47909
1972	90.71205
1973	117.96603
1974	137.08462
1975	107.59527
1976	90.85042
1977	66.02317
1978	50.84182
1979	46.65008
1980	36.47383
1981	25.06904
1982	21.84905
1983	18.38426
1984	17.90012
1985	17.11736
1986	20.37272
1987	25.53662
1988	32.68018
1989	44.64595
1990	50.62402
1991	48.69359
1992	50.59924
1993	48.25622
1994	46.16165
1995	36.90462
1996	34.23537
1997	24.51221
1998	28.14557
1999	35.89248
2000	40.91879
2001	49.09676
2002	61.82771
2003	72.1294
2004	85.32937
2005	89.0691
2006	107.22369
2007	139.33395
2008	166.63361
2009	171.25977
2010	161.74442
2011	159.07382
2012	135.17481
2013	121.75193
2014	116.16596
2015	120.67492
2016	141.37945