1/15/2011 - 285.6

2/1/2011 - 278.3

2/15/2011 - 274.4

3/1/2011 - 271.1

3/15/2011 - 266.9

4/1/2011 - 262.6

4/15/2011 - 258.9

5/1/2011 - 258.2

5/15/2011 - 251.7

6/1/2011 - 250.4

6/16/2011 - 246.7

7/1/2011 - 245.7

7/15/2011 - 244.8

8/1/2011 - 245.7

11/1/2011 - 251.5

11/15/2011 - 250.6

12/1/2011 - 246.5