Year Percent 1987-01-01 1.156961 1988-01-01 3.321320 1989-01-01 1.465201 1990-01-01 7.347401 1991-01-01 12.661320 1992-01-01 6.309899 1993-01-01 14.722360 1994-01-01 13.496430 1995-01-01 10.931920 1996-01-01 11.612420 1997-01-01 6.921649 1998-01-01 31.749600 1999-01-01 45.782250 2000-01-01 61.921390 2001-01-01 72.735020 2002-01-01 66.595080 2003-01-01 35.996440 2004-01-01 31.663190 2005-01-01 38.125480 2006-01-01 52.121920 2007-01-01 67.073240 2008-01-01 74.256200 2009-01-01 133.250000 2010-01-01 188.131500