Year Percent 1960-01-01 97.64270000000000 1961-01-01 97.64430000000000 1962-01-01 97.63570000000000 1963-01-01 97.83070000000000 1964-01-01 98.07450000000000 1965-01-01 98.21230000000000 1966-01-01 98.34000000000000 1967-01-01 98.41490000000000 1968-01-01 98.51480000000000 1969-01-01 98.56040000000000 1970-01-01 98.60060000000000 1971-01-01 98.65540000000000 1972-01-01 98.71400000000000 1973-01-01 98.83870000000000 1974-01-01 98.94270000000000 1975-01-01 99.05170000000000 1976-01-01 99.13840000000000 1977-01-01 99.17680000000000 1978-01-01 99.21740000000000 1979-01-01 99.19890000000000 1980-01-01 99.18460000000000 1981-01-01 99.14070000000000 1982-01-01 99.02799999999999 1983-01-01 98.99610000000000 1984-01-01 98.89820000000000 1985-01-01 98.90100000000001 1986-01-01 98.91210000000000 1987-01-01 98.84370000000000 1988-01-01 98.86860000000000 1989-01-01 98.68040000000000 1990-01-01 98.54930000000000 1991-01-01 98.57590000000000 1992-01-01 98.67280000000000 1993-01-01 99.03430000000000 1994-01-01 99.31270000000000 1995-01-01 99.38170000000000 1996-01-01 99.42130000000000 1997-01-01 99.45270000000000 1998-01-01 99.45270000000000 1999-01-01 99.66380000000000 2000-01-01 99.73940000000000 2001-01-01 99.67720000000000 2002-01-01 99.77900000000000 2003-01-01 99.90710000000000 2004-01-01 99.90260000000000 2005-01-01 99.90470000000000 2006-01-01 99.93150000000000 2007-01-01 99.89410000000000 2008-01-01 99.83130000000000 2009-01-01 99.83250000000000 2010-01-01 99.85770000000000 2011-01-01 99.81690000000000 2012-01-01 99.82710000000000 2013-01-01 99.86180000000000 2014-01-01 99.73820000000000 2015-01-01 98.40390000000000 2016-01-01 95.45320000000000