Period	Percent
1970-01-01	1.28
1975-01-01	1.50
1980-01-01	1.61
1985-01-01	1.99
1990-01-01	2.57
1995-01-01	3.35
2000-01-01	4.15
2005-01-01	5.50
2010-01-01	5.32