Year	% of total
1970	97.0446243739566
1971	97.08205238154348
1972	97.0467350939013
1973	97.20665891898518
1974	97.30075520193333
1975	97.36006616959556
1976	97.2204610731261
1977	97.08996989783822
1978	97.00088773332781
1979	97.0065342130625
1980	96.94046671000595
1981	96.9434270309162
1982	97.09141088178413
1983	96.88970300113535
1984	96.86350705185342
1985	96.90146771289575
1986	96.99908304437321
1987	97.08067391314796
1988	97.14290835872977
1989	96.9028164307129
1990	98.04511278195488
1991	98.1159420289855
1992	98.17927170868347
1993	98.07692307692307
1994	98.05555555555556
1995	98.0225988700565
1996	98.09004092769442
1997	98.04469273743017
1998	98.1294964028777
1999	98.08259587020649
2000	98.17351598173516
2001	98.21162444113264
2002	98.2089552238806
2003	98.30985915492958
2004	97.31543624161074
2005	97.32977303070761
2006	97.4715549936789
2007	97.30077120822622
2008	97.33840304182509