Year	Ratio
1971-01-01	0.0558100007474422
1972-01-01	0.0727799981832504
1973-01-01	0.1147499978542330
1974-01-01	0.2205400019884110
1975-01-01	0.1189299970865250
1976-01-01	0.1198699995875360
1979-01-01	0.1923000067472460
1980-01-01	0.2346100062131880
1981-01-01	0.3098599910736080
1982-01-01	0.3098399937152860
1984-01-01	0.3483099937438960
1985-01-01	0.3356600105762480
1986-01-01	0.3029899895191190
1987-01-01	0.3493500053882600
1988-01-01	0.3131400048732760
1989-01-01	0.3420000076293950
1990-01-01	0.3969100117683410
1991-01-01	0.3428300023078920
1992-01-01	0.3383300006389620
1993-01-01	0.3377699851989750
1998-01-01	0.3889600038528440
1999-01-01	0.4011299908161160
2000-01-01	0.3522500097751620
2001-01-01	0.3615300059318540
2002-01-01	0.4271599948406220
2004-01-01	0.3758099973201750
2005-01-01	0.3732900023460390
2006-01-01	0.4258599877357480
2010-01-01	0.4996100068092350
2011-01-01	0.4201700091362000
2012-01-01	0.4450199902057650
2013-01-01	0.4121100008487700
2014-01-01	0.3072000145912170