Year	Percent
1991-01-01	4.44600009918213
1992-01-01	4.41300010681152
1993-01-01	5.03499984741211
1994-01-01	5.53100013732910
1995-01-01	6.08799982070923
1996-01-01	6.57499980926514
1997-01-01	6.62900018692017
1998-01-01	7.74300003051758
1999-01-01	9.16800022125244
2000-01-01	9.12800025939941
2001-01-01	9.63300037384033
2002-01-01	9.92899990081787
2003-01-01	10.16399955749510
2004-01-01	9.43000030517578
2005-01-01	8.66899967193604
2006-01-01	8.01099967956543
2007-01-01	7.69199991226196
2008-01-01	7.25600004196167
2009-01-01	9.12600040435791
2010-01-01	9.40799999237061
2011-01-01	8.33899974822998
2012-01-01	8.09000015258789
2013-01-01	6.82200002670288
2014-01-01	6.28499984741211
2015-01-01	5.51300001144409
2016-01-01	5.15399980545044
2017-01-01	4.61800003051758