Year Percent 1989-01-01 2.3924600000000000 1990-01-01 2.1520700000000000 1991-01-01 2.1597700000000000 1992-01-01 2.3575000000000000 1993-01-01 2.9459700000000000 1994-01-01 3.1342500000000000 1995-01-01 3.0973000000000000 1996-01-01 3.3660699999999997 1997-01-01 3.5399199999999995 1998-01-01 3.5481300000000005 1999-01-01 3.4903500000000000 2000-01-01 3.7475699999999996 2001-01-01 4.3450400000000000 2002-01-01 5.0371200000000000 2003-01-01 6.2737300000000005 2004-01-01 6.3021300000000000 2005-01-01 6.3304400000000000 2006-01-01 8.6782100000000000 2007-01-01 8.9496100000000000 2008-01-01 8.0725300000000000 2009-01-01 9.4799100000000000 2010-01-01 11.7428000000000000 2011-01-01 15.9327000000000000 2012-01-01 15.1228000000000000 2013-01-01 13.9722000000000000 2014-01-01 15.1033000000000000 2015-01-01 16.7887000000000000 2016-01-01 16.6513000000000000