Year Percent 1980-01-01 2.44819000000000030 1981-01-01 3.62461999999999970 1982-01-01 3.75451000000000000 1983-01-01 3.63346999999999950 1984-01-01 2.87883000000000000 1985-01-01 0.21996600000000000 1986-01-01 0.25310500000000000 1987-01-01 0.30853900000000000 1988-01-01 0.23376100000000002 1989-01-01 0.21869400000000000 1990-01-01 8.81657000000000000 1991-01-01 7.21808999999999900 1992-01-01 6.27863000000000100 1993-01-01 5.62284000000000000 1994-01-01 5.29273000000000100 1995-01-01 4.79140000000000000 1996-01-01 4.35935000000000000 1997-01-01 3.87413000000000000 1998-01-01 4.41971000000000000 1999-01-01 6.25036000000000000 2000-01-01 7.50369000000000000 2001-01-01 8.40709000000000000 2002-01-01 9.39580000000000000 2003-01-01 9.72681000000000000 2004-01-01 9.45280000000000000 2005-01-01 8.75701000000000100 2006-01-01 7.87513000000000000 2007-01-01 6.56779000000000000 2008-01-01 5.09594000000000100 2009-01-01 4.32868000000000000 2010-01-01 3.54413000000000040 2011-01-01 3.12902000000000000 2012-01-01 4.95181000000000000 2013-01-01 10.11010000000000000 2014-01-01 11.21690000000000000 2015-01-01 12.36040000000000000 2016-01-01 12.57760000000000000