Year	% of total
1970	66.97742783899602
1971	84.55588920359082
1972	75.04919818175674
1973	61.29042147947899
1974	84.90803336292696
1975	85.32627801479723
1976	85.52423845648195
1977	68.48186098557275
1978	61.760251317714484
1979	68.5834945909374
1980	61.3692800350511
1981	66.83889899746691
1982	67.50474526583233
1983	46.610971185980546
1984	67.57265779388196
1985	74.69381758022226
1986	67.39130746722189
1987	56.99378190187283
1988	67.20700364404182
1989	83.23190342856186
1990	99.14841849148418
1991	99.16567342073897
1992	99.16067146282974
1993	99.15356711003628
1994	99.14320685434517
1995	99.1745283018868
1996	99.19908466819221
1997	99.34569247546347
1998	99.24242424242425
1999	99.15074309978769
2000	99.16753381893861
2001	98.96907216494846
2002	98.88059701492537
2003	98.76390605686032
2004	98.86934673366834
2005	98.80952380952381
2006	98.77777777777777
2007	98.77425944841676
2008	98.78542510121457