Year	% of total
1970	72.69447828579621
1971	77.553770242915
1972	50.71907291088148
1973	69.24889866641982
1974	76.6225677622501
1975	76.86556478860378
1976	65.36997430875282
1977	50.39273918943138
1978	67.45181699214817
1979	57.52071256834201
1980	57.71456889976484
1981	62.424000373493826
1982	28.700569246456332
1983	48.95908226948231
1984	62.40227737883948
1985	61.21390351961362
1986	49.79734568775415
1987	37.61063309077138
1988	64.67267726044933
1989	64.88869906860666
1990	91.72982988041099
1991	91.67927382753403
1992	91.8738826588656
1993	91.6735639794736
1994	91.82288299935358
1995	91.8027687043086
1996	91.74311926605505
1997	91.0889546658358
1998	90.91741718821554
1999	90.38101186758276
2000	89.57317073170732
2001	89.37623311579907
2002	89.47445469184599
2003	89.30854154561302
2004	89.35479316673725
2005	89.27528168034497
2006	89.30749424041198
2007	89.30700940771167
2008	89.41493456505005