Year	% of total
1990	62.583900683784364
1991	63.81997920567642
1992	63.968732506383304
1993	63.56071311317375
1994	60.851308958645305
1995	60.7981890340176
1996	59.586000135359846
1997	60.18456029847721
1998	58.14485845202585
1999	57.61054049314765
2000	57.92127424373796
2001	57.508261694971324
2002	57.30319414139856
2003	56.68268602277462
2004	55.191846331186106
2005	54.81703449034775
2006	56.09679205189995
2007	55.53495537794265
2008	54.9504436836558
2009	54.019741336356475
2010	55.12329242400113
2011	56.103919278555026
2012	54.095982818854374
2013	55.93063241691019
2014	54.52597222727032
2015	53.36112213881901
2016	52.119351545158565