Year	Percent
1980	2.65233
1981	2.91319
1982	3.24558
1983	2.90295
1984	3.05504
1985	3.0158
1986	2.9414
1987	2.76269
1988	2.59206
1989	1.81712
1990	2.61249
1991	2.25165
1992	2.231
1993	2.46919
1994	2.27323
1995	1.95551
1996	1.96792
1997	2.03131
1998	2.01908
1999	1.90114
2000	1.83034
2001	1.90564
2002	1.90064
2003	1.90804
2004	1.87324
2005	1.92613
2006	1.92004
2007	2.00187
2008	1.75146
2009	1.79718
2010	1.83388
2011	1.78802
2012	1.79613
2013	1.76945
2014	1.89766
2015	2.13953
2016	1.95136
2017	1.95679