Year	% of total
1990	71.15642729928712
1991	72.29233585024092
1992	66.87098972841616
1993	73.61259935593814
1994	76.08058938353186
1995	75.54160566213194
1996	71.48875053410988
1997	70.76848841448759
1998	68.75411652984052
1999	72.82134056285656
2000	70.91724252838392
2001	64.90636187519627
2002	62.346344468624785
2003	64.27139770299021
2004	65.28952422109539
2005	63.758859736160645
2006	64.61710616918874
2007	64.76239499532628
2008	64.49375967163
2009	65.3535217684024
2010	60.539985516791354
2011	59.87957745186384
2012	56.89067275892966
2013	54.064293015580624
2014	54.97933892215305
2015	52.72027027570244
2016	53.59980883789202