Year	Percent
1991-01-01	58.8709983825684
1992-01-01	58.9840011596680
1993-01-01	58.7159996032715
1994-01-01	59.7060012817383
1995-01-01	60.3819999694824
1996-01-01	60.7569999694824
1997-01-01	60.9059982299805
1998-01-01	56.4869995117188
1999-01-01	56.8059997558594
2000-01-01	58.4269981384277
2001-01-01	58.8139991760254
2002-01-01	59.8310012817383
2003-01-01	59.2150001525879
2004-01-01	59.8160018920898
2005-01-01	59.7669982910156
2006-01-01	59.8440017700195
2007-01-01	59.9150009155273
2008-01-01	59.4539985656738
2009-01-01	58.4490013122559
2010-01-01	58.5029983520508
2011-01-01	58.8269996643066
2012-01-01	59.1829986572266
2013-01-01	59.3779983520508
2014-01-01	60.0849990844727
2015-01-01	60.1920013427734
2016-01-01	60.3180007934570
2017-01-01	60.2939987182617