Quarterly
1977-03-31 12
1977-06-30 8.2
1977-09-30 7.1
1977-12-31 5.9
1978-03-31 6.8
1978-06-30 9.1
1978-09-30 9.8
1978-12-31 11.7
1979-03-31 12.7
1979-06-30 12.3
1979-09-30 14.1
1979-12-31 15.8
1980-03-31 17.6
1980-06-30 17.1
1980-09-30 16.1
1980-12-31 15.5
1981-03-31 13.3
1981-06-30 12.4
1981-09-30 14.2
1981-12-31 15.5
1982-03-31 14.3
1982-06-30 13.3
1982-09-30 11.4
1982-12-31 9.9
1983-03-31 11.1
1983-06-30 10.1
1983-09-30 9.8
1983-12-31 9.3
1984-03-31 9.2
1984-06-30 9.2
1984-09-30 11.1
1984-12-31 10.1
1985-03-31 13
1985-06-30 12.6
1985-09-30 11.7
1985-12-31 11.6
1986-03-31 12.4
1986-06-30 10.1
1986-09-30 9.9
1986-12-31 11.2
1987-03-31 10.6
1987-06-30 9.1
1987-09-30 9.8
1987-12-31 9.2
1988-03-31 9
1988-06-30 8.4
1988-09-30 11.3
1988-12-31 12.5
1989-03-31 13
1989-06-30 13.4
1989-09-30 13.9
1989-12-31 15.1
1990-03-31 15.2
1990-06-30 15.1
1990-09-30 14.9
1990-12-31 13.8
1991-03-31 13.2
1991-06-30 11.5
1991-09-30 10.7
1991-12-31 10.5
1992-03-31 10.5
1992-06-30 10.2
1992-09-30 10.1
1992-12-31 7.5
1993-03-31 6.3
1993-06-30 5.9
1993-09-30 5.9
1993-12-31 5.5
1994-03-31 5.2
1994-06-30 5.1
1994-09-30 5.4
1994-12-31 6.1
1995-03-31 6.6
1995-06-30 6.7
1995-09-30 6.8
1995-12-31 6.6
1996-03-31 6.2
1996-06-30 5.9
1996-09-30 5.7
1996-12-31 6.2
1997-03-31 6.2
1997-06-30 6.5
1997-09-30 7.1
1997-12-31 7.4
1998-03-31 7.4
1998-06-30 7.5
1998-09-30 7.6
1998-12-31 6.5
1999-03-31 5.5
1999-06-30 4.9
1999-09-30 4.6
1999-12-31 4.9
2000-03-31 5.2
2000-06-30 5.5
2000-09-30 5.5
2000-12-31 5.4
2001-03-31 5.2
2001-06-30 4.8
2001-09-30 4.6
2001-12-31 3.9
2002-03-31 3.6
2002-06-30 3.7
2002-09-30 3.7
2002-12-31 3.6
2003-03-31 3.6
2003-06-30 3.5
2003-09-30 3.2
2003-12-31 3.3
2004-03-31 3.5
2004-06-30 3.8
2004-09-30 4.3
2004-12-31 4.4
2005-03-31 4.4
2005-06-30 4.5
2005-09-30 4.3
2005-12-31 4.2
2006-03-31 4.2
2006-06-30 4.2
2006-09-30 4.4
2006-12-31 4.6
2007-03-31 4.9
2007-06-30 5.1
2007-09-30 5.5
2007-12-31 5.7
2008-03-31 5.3
2008-06-30 5.2
2008-09-30 5.2
2008-12-31 4.4
2009-03-31 2.3
2009-06-30 1.6
2009-09-30 1.3
2009-12-31 1.1
2010-03-31 1
2010-06-30 1.2
2010-09-30 1.2
2010-12-31 1.3
2011-03-31 1.5
2011-06-30 1.7
2011-09-30 1.7
2011-12-31 1.7
2012-03-31 1.6
2012-06-30 1.7
2012-09-30 1.8
2012-12-31 1.8
2013-03-31 1.6
2013-06-30 1.5
2013-09-30 1.5