Period	Percent
1970-01-01	0.50
1975-01-01	0.80
1980-01-01	1.01
1985-01-01	1.33
1990-01-01	1.43
1995-01-01	1.43
2000-01-01	1.26
2005-01-01	0.80
2010-01-01	2.98