Year	% of total
1970	4.48010149505687
1971	4.396255755880942
1972	4.621085892410222
1973	4.183107224551671
1974	4.20665806705428
1975	4.276091659722748
1976	3.9400921049104745
1977	3.7135276048127213
1978	3.346638210276128
1979	3.638520578812985
1980	3.6659371421713978
1981	3.177388710356863
1982	3.3521009559435773
1983	2.991849346033819
1984	3.3013921313211543
1985	3.1609630035631984
1986	2.976350899226364
1987	3.090415505019566
1988	3.1018876322861493
1989	2.703972894855748
1990	4.40251572327044
1991	4.958677685950414
1992	5.3097345132743365
1993	4.273504273504273
1994	2.9197080291970803
1995	2.2556390977443606
1996	2.5210084033613445
1997	3.5398230088495577
1998	3.418803418803419
1999	4.464285714285714
2000	4.23728813559322
2001	5.217391304347826
2002	4.651162790697675
2003	4.580152671755725
2004	5.511811023622047
2005	5.46875
2006	5.737704918032787
2007	5.737704918032787
2008	6.140350877192982