Year	Ratio
1970-01-01	0.571770012378693
1971-01-01	0.574129998683929
1972-01-01	0.581960022449493
1973-01-01	0.592830002307892
1974-01-01	0.593140006065369
1975-01-01	0.594699978828430
1976-01-01	0.605499982833862
1977-01-01	0.608340024948120
1978-01-01	0.622619986534119
1979-01-01	0.632640004158020
1980-01-01	0.646780014038086
1981-01-01	0.664300024509430
1982-01-01	0.675779998302460
1983-01-01	0.684520006179810
1984-01-01	0.694549977779388
1985-01-01	0.698499977588654
1986-01-01	0.704010009765625
1987-01-01	0.704670011997223
1988-01-01	0.705590009689331
1989-01-01	0.708909988403320
1990-01-01	0.711310029029846
1991-01-01	0.706619977951050
1992-01-01	0.714410006999969
1993-01-01	0.714139997959137
1994-01-01	0.720539987087250
1995-01-01	0.730440020561218
1996-01-01	0.732689976692200
1997-01-01	0.737670004367828
1998-01-01	0.754010021686554
1999-01-01	0.746909976005554
2000-01-01	0.752200007438660
2001-01-01	0.768140017986298
2002-01-01	0.742290019989014
2003-01-01	0.801209986209869
2006-01-01	0.796570003032684
2007-01-01	0.798179984092712
2008-01-01	0.797100007534027
2009-01-01	0.817059993743896
2011-01-01	0.837989985942841
2012-01-01	0.849129974842072
2013-01-01	0.863049983978271
2014-01-01	0.869610011577606
2015-01-01	0.880320012569427
2016-01-01	0.894200026988983