Year	% of total
1970	0.9732028360873163
1971	1.0336575108401223
1972	1.042128991365056
1973	1.0346710591583252
1974	1.4746433733221116
1975	1.3450186224277128
1976	1.2965050802668958
1977	1.0856857201373176
1978	1.3354430124539736
1979	1.302714573922566
1980	1.0787131361550657
1981	1.336852951246059
1982	1.1692452907631716
1983	1.279976627127287
1984	1.3755048543384865
1985	1.5337934158885622
1986	1.5442604055989801
1987	1.4834296142274308
1988	1.5591314885592296
1989	1.409843721889706
1990	1.1725293132328307
1991	0.8620689655172413
1992	0.8333333333333334
1993	0.7963594994311717
1994	0.7675438596491228
1995	0.7415254237288136
1996	0.7414272474513438
1997	0.7359705611775529
1998	0.7220216606498195
1999	0.6739679865206403
2000	0.612088752869166
2001	0.8130081300813009
2002	0.7493755203996669
2003	0.7053291536050157
2004	0.6782215523737753
2005	0.63875088715401
2006	0.6258692628650904
2007	0.6578947368421052
2008	0.6422607578676942