Year	Percent
1991-01-01	25.1677242146546
1992-01-01	25.0241467600642
1993-01-01	26.1076818525009
1994-01-01	25.8633458694355
1995-01-01	26.8192094698939
1996-01-01	26.2174706995105
1997-01-01	26.4435864329566
1998-01-01	26.2498720349208
1999-01-01	24.2466118469467
2000-01-01	23.6826264121099
2001-01-01	24.8119329537200
2002-01-01	24.9542799760055
2003-01-01	24.3583146319125
2004-01-01	24.9389568830782
2005-01-01	24.1954789617184
2006-01-01	22.4555821543262
2007-01-01	22.7361911906236
2008-01-01	22.8159874147292
2009-01-01	23.9517905629302
2010-01-01	23.9226716232196
2011-01-01	23.4995582998268
2012-01-01	23.0351406844322
2013-01-01	23.7827442521839
2014-01-01	23.1152941913955
2015-01-01	23.1979014236387
2016-01-01	23.4644831968767
2017-01-01	23.2371429615900