Year	% of total
1971	1.0035191905861651
1972	1.483109729907274
1973	0.9326273862146014
1974	0.9318497913769123
1975	0.6295199093839854
1976	1.2108897136577579
1977	1.1720123451967026
1978	1.118047144321252
1979	1.1707545513083182
1980	1.1394712853236098
1981	1.1198835321126603
1982	1.097955971965524
1983	1.0591163439303808
1984	1.0340548738453053
1985	1.0323291065191582
1986	0.99000099000099
1987	0.9646922631680493
1988	0.9326328224577983
1989	0.9212203098370975
1990	0.6182653241476771
1991	0.6318617532919832
1992	0.6519125590531182
1993	0.6785555972312204
1994	0.6610834232475296
1995	0.7907552620718118
1996	1.6232392711091614
1997	1.7923602784309451
1998	2.002352067343402
1999	2.6933088109228636
2000	2.319265954382741
2001	2.1284047740927337
2002	2.1119810513849595
2003	1.9126738794435858
2004	1.8415085332378567
2005	1.7941926743235161
2006	1.8731919573481244
2007	1.5610045121006335
2008	1.2221621946095205
2009	1.1943845550764407
2010	1.5964928732183046
2011	1.6098921360744904
2012	1.7061381752742626
2013	2.3544321458468978
2014	2.122308921688446
2015	2.74038927084342