Year	Percent
1981	104.63715
1982	95.76068
1983	90.48293
1984	75.53535
1985	82.80338
1986	83.60239
1987	70.01252
1988	68.15448
1989	63.33685
1990	61.34695
1991	65.36749
1992	60.6611
1993	57.26536
1994	57.26247
1995	46.35648
1996	44.02049
1997	43.39594
1998	41.47362
1999	43.4846
2000	47.47654
2001	44.45679
2002	34.1264
2003	36.73015
2004	37.62079
2005	37.94527
2006	36.57482
2007	36.67336
2008	37.365
2009	35.69598
2010	24.92626
2011	28.02099
2012	26.98047
2013	25.74232
2014	24.64361
2015	20.16078
2016	18.17313
2017	22.32013