Year	Percent
1980	14.49081
1981	15.29841
1982	15.7107
1983	12.8378
1984	3.51669
1985	8.89178
1986	10.66807
1987	15.22045
1988	11.89828
1989	17.74782
1990	16.18479
1991	16.36838
1992	14.51936
1993	20.81817
1994	22.24687
1995	21.2215
1996	22.79891
1997	18.10513
1998	16.92688
1999	15.95628
2000	18.49521
2001	25.51232
2002	29.36802
2003	32.42928
2004	33.99739
2005	29.68265
2006	31.8353
2007	40.67218
2008	40.56043
2009	52.32929
2010	52.06266
2011	56.15026
2012	76.27605
2013	115.23563
2014	118.00608
2015	150.03286
2016	99.68365