Year	% of total
1971	36.4656381486676
1972	26.547619047619047
1973	25.66079295154185
1974	31.772151898734176
1975	25.402504472271914
1976	22.63195950831526
1977	15.455746367239101
1978	17.75407779171895
1979	16.34958382877527
1980	11.987704918032787
1981	16.77344205008736
1982	24.90613266583229
1983	45.82172701949861
1984	32.50327653997378
1985	33.82173382173382
1986	89.52811893988365
1987	79.42028985507247
1988	80.43478260869566
1989	79.64728312678741
1990	78.59103385178408
1991	75.15310586176727
1992	50.13860013860014
1993	53.477051460361615
1994	52.794830371567045
1995	53.826530612244895
1996	55.502818154850196
1997	53.097090175741855
1998	48.78815080789946
1999	45.53347482153193
2000	41.69973544973545
2001	37.5618917534574
2002	31.497334840898077
2003	37.85926660059465
2004	33.35066961383435
2005	36.51385265250342
2006	40.448199853049225
2007	34.61626313385107
2008	42.154163799036475
2009	32.51906709406433
2010	43.281232430001126
2011	45.4852412591221
2012	47.36506587335317
2013	46.91532258064516
2014	45.18173345759553
2015	35.04250316512932