Year	% of total
1971	60.92907507258399
1972	41.02141680395387
1973	60.99568796550372
1974	56.982075864943724
1975	45.103503184713375
1976	45.225758697261284
1977	53.86465132256957
1978	52.86871961102106
1979	43.551088777219434
1980	75.63043478260869
1981	78.98832684824903
1982	81.38401559454192
1983	97.87697332607512
1984	98.33978970669618
1985	97.65400332980172
1986	98.35490830636462
1987	96.14773629864972
1988	77.76502653851671
1989	68.19849729163026
1990	94.156367544331
1991	87.0921783729876
1992	89.02123834138668
1993	91.48909501128102
1994	98.01811261320384
1995	92.84921515776122
1996	86.4767616191904
1997	90.73866815892558
1998	95.67307692307693
1999	76.45259938837921
2000	92.92303637322088
2001	99.3945945945946
2002	99.27121290994275
2003	99.42883785989042
2004	80.9726237034518
2005	86.9955740692528
2006	63.98433327398968
2007	85.60364948016127
2008	51.31713992473487
2009	59.32107815495659
2010	78.81764438381083
2011	62.635344160866204
2012	51.15598754364443
2013	70.36528897273196
2014	74.13753361505955
2015	60.16011644832605