Year	% of total
1960	0.7360904601942104
1961	0.8944986564842314
1962	0.9589689814971417
1963	1.01341707108193
1964	1.1041057045461402
1965	1.2756237206680707
1966	1.490436246480713
1967	1.8258446829875403
1968	2.2753234333076535
1969	2.9582917082917084
1970	3.5882055358820555
1971	3.617292766585112
1972	3.5586081196723676
1973	3.6656011695013255
1974	3.6513943801932474
1975	3.8743946258397126
1976	4.073774559355988
1977	3.966080039205734
1978	3.7972212556122322
1979	4.048297808863991
1980	3.847155677988176
1981	4.262016543706684
1982	4.19757160972051
1983	4.338690491695102
1984	4.327946993002264
1985	4.012401519761839
1986	4.3029886359040725
1987	4.3277148688368285
1988	4.463940667165492
1989	4.612003322719092
1990	5.847808520358631
1991	5.431202115860422
1992	5.180597314849869
1993	5.430895006104296
1994	5.540165121412803
1995	6.059178235294118
1996	6.08793003489812
1997	6.258681484490614
1998	6.843162589114662
1999	6.8668722894685725
2000	7.714452335057996
2001	8.09462772479564
2002	8.062089947089946
2003	8.66308733624454
2004	9.015022198661454
2005	9.298007964161274
2006	9.174213123626986
2007	9.132101988065227
2008	9.334008822003115
2009	9.293944022068224
2010	9.348079938802831
2011	9.465320519012202
2012	10.328283500906545
2013	10.545098716186772
2014	10.74407643312102
2015	10.915366891541254
2016	11.181817575231868