Year	% of total
1990	95.32608337108846
1995	95.19054942774979
2000	95.23554187503771
2005	95.46722761451002
2010	95.17598221919947
2011	95.80233982442168
2012	94.51511930950765
2013	93.78141242852374
2014	92.72570324075905
2015	92.6547958786776
2016	91.38625709853748
2017	91.37035328798244