Year	Percent
1960-01-01	5.99738009457189
1961-01-01	7.33914401726247
1962-01-01	6.28342657464474
1963-01-01	6.59746593035339
1964-01-01	6.33620077779178
1965-01-01	5.65277334301074
1966-01-01	4.93101241840364
1967-01-01	5.26453330886836
1968-01-01	4.85700014245268
1969-01-01	4.76450809134903
1970-01-01	5.96880873623333
1971-01-01	7.02850976353000
1972-01-01	6.74439868825401
1973-01-01	6.10204136069063
1974-01-01	6.82089382720062
1975-01-01	9.42709473540859
1976-01-01	8.74513122877774
1977-01-01	8.28549139479554
1978-01-01	7.27575833057583
1979-01-01	6.91918328354390
1980-01-01	7.51716166348935
1981-01-01	8.02201290072703
1982-01-01	9.57138681594439
1983-01-01	9.34001161974951
1984-01-01	7.72785895300775
1985-01-01	7.52228292201472
1986-01-01	7.17459724557096
1987-01-01	6.28592799772700
1988-01-01	5.63289747871720
1989-01-01	5.42279427980682
1990-01-01	5.58968196221281
1991-01-01	6.52329946558976
1992-01-01	7.09663269675256
1993-01-01	6.69800888445659
1994-01-01	6.08371338101417
1995-01-01	5.66614494113597
1996-01-01	5.46458993150315
1997-01-01	5.05367134261210
1998-01-01	4.65452251407526
1999-01-01	4.36888465674556
2000-01-01	4.13736102634815
2001-01-01	4.70272934820425
2002-01-01	5.66258405909818
2003-01-01	5.72918668870856
2004-01-01	5.46477039153700
2005-01-01	5.15067789199065
2006-01-01	4.68487007213986
2007-01-01	4.55330688620426
2008-01-01	5.47854327068330
2009-01-01	8.14888774350760
2010-01-01	8.72574858547154
2011-01-01	8.54880995218320
2012-01-01	7.96817810184140
2013-01-01	7.17619703644062
2014-01-01	6.13477029970948
2015-01-01	5.25354578281929
2016-01-01	4.84055747741148
2017-01-01	4.33722879582151