Year	Percent
1981	50.77704
1982	52.93054
1983	56.42511
1984	78.57115
1985	81.59138
1986	64.04991
1987	60.2858
1988	57.79442
1989	47.07899
1990	61.89507
1991	29.80221
1992	61.24717
1993	99.16689
1994	66.3198
1995	61.15008
1996	65.02098
1997	87.81184
1998	85.82048
1999	91.43107
2000	101.24056
2001	91.40393
2002	86.97827
2003	88.8173
2004	94.9165
2005	89.13514
2006	88.70389
2007	94.59977
2008	109.45871
2009	88.00244
2010	85.91996
2011	109.66496
2012	90.48489
2013	84.46031
2014	90.05837
2015	72.0602
2016	73.98785
2017	91.71446