Period	Percent
1970-01-01	0.22
1975-01-01	0.30
1980-01-01	0.58
1985-01-01	0.75
1990-01-01	1.01
1995-01-01	1.18
2000-01-01	1.38
2005-01-01	1.91
2010-01-01	1.83