Year	Percent
1981	3.92805
1982	6.84346
1983	10.54683
1984	14.71792
1985	22.53339
1986	29.15823
1987	29.74638
1988	40.40622
1989	47.47679
1990	57.32619
1991	119.41603
1992	116.28346
1993	114.48346
1994	103.40422
1995	82.1655
1996	106.74409
1997	102.40536
1998	79.48873
1999	88.61406
2000	93.6367
2001	79.62273
2002	73.71645
2003	66.57649
2004	62.95524
2005	61.88678
2006	83.72032
2007	105.52047
2008	101.8552
2009	111.0797
2010	102.17733
2011	85.66569
2012	96.46174
2013	94.39248
2014	85.49587
2015	81.55108
2016	76.39132