Year	Percent
1971	87.75525
1972	87.38424
1973	84.59438
1974	86.59138
1975	79.1223
1976	78.65077
1977	72.23928
1978	77.63688
1979	83.596
1980	73.07264
1981	89.33345
1982	77.81579
1983	78.40547
1984	76.00438
1985	58.13023
1986	61.31049
1987	68.53172
1988	78.93495
1989	78.21712
1990	78.59986
1991	83.33194
1992	82.68611
1993	100.76701
1994	104.23888
1995	99.69097
1996	97.15772
1997	98.86197
1999	100.71855
2000	97.6595
2001	98.04249
2002	100.45012
2003	101.18464
2004	87.55183
2005	100.0818
2006	101.14621
2007	99.95163
2008	100.24621
2009	103.16041
2010	99.31649
2011	101.7331
2012	100.06414
2013	98.33207
2014	99.82538
2015	96.81906