Period	Percent
1970-01-01	1.20
1975-01-01	1.64
1980-01-01	2.32
1985-01-01	3.60
1990-01-01	1.90
1995-01-01	2.13
2000-01-01	2.64
2005-01-01	3.46
2010-01-01	5.28