Period	Percent
1970-01-01	1.30
1975-01-01	1.43
1980-01-01	2.28
1985-01-01	3.83
1990-01-01	4.84
1995-01-01	5.46
2000-01-01	5.30
2005-01-01	5.21
2010-01-01	6.22