Year	Percent
1977	1.78232
1978	2.4331
1979	2.45842
1980	2.42354
1981	2.1661
1982	2.19956
1983	2.25587
1984	2.0308
1985	1.84112
1986	1.63451
1987	1.42929
1988	1.26009
1989	1.25287
1990	1.27597
1991	1.38452
1992	1.63271
1993	1.74805
1994	1.81809
1995	1.69334
1996	1.65258
1997	1.49484
1998	1.64721
1999	1.68451
2000	1.43521
2001	1.29004
2002	1.30379
2003	1.47095
2004	1.54586
2005	1.91419
2006	1.84027
2007	1.84025
2008	2.05697
2009	2.12321
2010	2.25416
2011	2.1498
2012	1.86177
2013	1.86599
2014	1.81089
2015	1.68706
2016	1.60181
2017	1.75285