Period	Percent
1970-01-01	0.22
1975-01-01	0.20
1980-01-01	0.45
1985-01-01	0.85
1990-01-01	1.45
1995-01-01	2.13
2000-01-01	2.18
2005-01-01	2.06
2010-01-01	1.93