Year	Percent
1991-01-01	52.3139991760254
1992-01-01	52.3909988403320
1993-01-01	52.3629989624023
1994-01-01	52.3689994812012
1995-01-01	52.3450012207031
1996-01-01	52.2809982299805
1997-01-01	52.2159996032715
1998-01-01	52.1590003967285
1999-01-01	52.1450004577637
2000-01-01	52.1759986877441
2001-01-01	52.3170013427734
2002-01-01	52.4860000610352
2003-01-01	52.6360015869141
2004-01-01	52.7999992370605
2005-01-01	52.9729995727539
2006-01-01	53.1370010375977
2007-01-01	53.2890014648438
2008-01-01	53.4300003051758
2009-01-01	53.5629997253418
2010-01-01	53.6879997253418
2011-01-01	53.8219985961914
2012-01-01	53.9169998168945
2013-01-01	53.8479995727539
2014-01-01	53.7779998779297
2015-01-01	53.6739997863770
2016-01-01	53.6069984436035
2017-01-01	53.6669998168945