Year	Percent
1960	1.592
1961	1.85507
1962	3.10417
1963	2.40794
1964	1.84375
1965	1.85714
1966	2.91492
1967	3.36095
1968	2.85595
1969	3.76289
1970	6.07293
1971	5.32268
1972	3.70968
1973	3.98486
1974	3.29127
1975	2.25397
1976	1.96862
1977	2.46399
1978	3.79923
1979	3.22075
1980	2.92236
1981	1.75511
1982	2.24053
1997	4.07803
1998	5.29744
1999	3.78386
2000	3.14686
2001	2.41351
2002	2.06924
2003	2.07205
2004	2.07107
2005	1.52811
2006	1.12034
2007	0.87061
2008	1.15398
2012	2.7646
2013	5.63852
2014	11.42533