Year	%
1972	39.17169
1973	34.18135
1974	46.88227
1975	52.87986
1976	56.3841
1977	61.04403
1978	63.72437
1979	64.68405
1981	73.93453
1983	86.25104
1984	84.97673
1988	88.82153
1989	88.8169
1990	88.11189
1991	89.81241
1992	89.88089
1993	89.7464
1994	89.09444
1995	88.851
1996	91.64545
1998	91.6497
1999	96.78057
2000	94.1204
2001	94.82403
2002	94.73648
2003	94.28978
2004	94.2989
2005	93.12243
2006	93.97279
2007	95.98997
2009	97.79176
2010	97.06229
2011	95.32419
2012	96.95983
2013	98.7568
2014	97.96364
2015	97.81033
2017	98.3805