| Date | Acquired | Amount |
|---|---|---|
| Oct 29, 2014 |
|
Undisclosed amount |
| Mar 23, 2011 |
|
$ 940,000,000 |
| Mar 22, 2006 |
|
$ 100,000,000 |
| Dec 18, 2003 |
|
Undisclosed amount |
| Feb 14, 1992 |
|
$ 670,000,000 |
