Year	% of total
1971	99.23427055638267
1972	99.19000055593648
1973	99.05091605959349
1974	98.90270350198391
1975	98.89465873401456
1976	98.9377577249055
1977	99.9299357205667
1978	99.94296089734938
1979	99.94444938762062
1980	99.95447692807946
1981	99.95094577081336
1982	99.9226498635707
1983	99.91859609440633
1984	99.92599009603038
1985	99.9961794307428
1988	99.8486508541941
1989	99.87863354902487
1990	98.13195697810696
1991	98.19656570886185
1992	98.52817198350093
1993	98.45020586294481
1994	98.467580042131
1995	98.55367270515791
1996	98.58591983185747
1997	98.57261673993177
1998	98.56278640300879
1999	98.5394047244833
2000	98.4559406997705
2001	98.00084862681469
2002	97.98188052275763
2003	96.96364962047554
2004	97.67449452717707
2005	97.89825813949413
2006	97.89538436936017
2007	98.41011895324255
2008	98.00535381872302
2009	97.96266522069853
2010	97.34740254620974
2011	95.99311454770452
2012	97.3210912123282
2013	97.61826838848705
2014	97.60844665052329