Year	% of total
1970	1.5223087032351568
1971	1.8831676230495815
1972	1.6718491805919606
1973	1.365290746130173
1974	1.9786455037484267
1975	2.022323270412351
1976	2.06443433580729
1977	1.6229549337889793
1978	1.4477387401989046
1979	1.6507814969519075
1980	1.5448360420992342
1981	1.7169807219043425
1982	1.7458179054719332
1983	1.2474292717802067
1984	1.7075483422570017
1985	1.8954064229967384
1986	1.7695659300377038
1987	1.455521657390283
1988	1.734616191654724
1989	2.226474516267208
1990	1.9202363367799113
1991	1.9817073170731707
1992	2.0289855072463765
1993	2.1398002853067046
1994	2.127659574468085
1995	2.2535211267605635
1996	2.292263610315186
1997	2.187902187902188
1998	2.0481927710843375
1999	2.2304832713754648
2000	2.195121951219512
2001	2.3030303030303028
2002	2.249718785151856
2003	2.0746887966804977
2004	2.048780487804878
2005	2.06961429915334
2006	2.05799812909261
2007	2.0758122743682312
2008	2.0442930153321974