| Date | Acquired | Amount |
|---|---|---|
| Apr 01, 2016 | Undisclosed amount | |
| Jan 25, 2016 | Undisclosed amount | |
| Sep 03, 2015 | $ 238,000,000 | |
| Aug 31, 2015 | Undisclosed amount | |
| Jun 08, 2015 | Undisclosed amount | |
| May 22, 2014 | Undisclosed amount | |
| May 06, 2014 | $ 101,000,000 | |
| Jan 23, 2014 | $ 90,700,000 | |
| Aug 07, 2013 | Undisclosed amount | |
| Jun 10, 2013 | Undisclosed amount | |
| Feb 13, 2013 | Undisclosed amount | |
| Mar 15, 2012 | Undisclosed amount | |
| Mar 04, 2011 | Undisclosed amount | |
| Feb 07, 2011 | $ 315,000,000 | |
| Dec 20, 2010 | Undisclosed amount | |
| Dec 02, 2010 | Undisclosed amount | |
| Sep 28, 2010 | Undisclosed amount | |
| Sep 28, 2010 | Undisclosed amount | |
| Sep 28, 2010 | Undisclosed amount | |
| Aug 31, 2010 | Undisclosed amount | |
| Jul 15, 2009 | Undisclosed amount | |
| Jun 11, 2009 | Undisclosed amount | |
| Jun 11, 2009 | Undisclosed amount | |
| Apr 19, 2009 | Undisclosed amount | |
| Dec 08, 2008 | Undisclosed amount | |
| Aug 01, 2008 | Undisclosed amount | |
| Jul 01, 2008 | Undisclosed amount | |
| Mar 13, 2008 | $ 850,000,000 | |
| Feb 03, 2008 | Undisclosed amount | |
| Feb 01, 2008 | Undisclosed amount | |
| Nov 11, 2007 | Undisclosed amount | |
| Nov 07, 2007 | $ 340,000,000 | |
| Jul 24, 2007 | Undisclosed amount | |
| May 15, 2007 | Undisclosed amount | |
| Nov 06, 2006 | Undisclosed amount | |
| Aug 16, 2006 | Undisclosed amount | |
| Aug 14, 2006 | Undisclosed amount | |
| May 18, 2006 | Undisclosed amount | |
| Jan 10, 2006 | Undisclosed amount | |
| Nov 03, 2005 | Undisclosed amount | |
| Oct 16, 2005 | Undisclosed amount | |
| Aug 04, 2005 | Undisclosed amount | |
| Aug 04, 2005 | Undisclosed amount | |
| Jun 24, 2004 | $ 435,000,000 | |
| Nov 19, 2003 | Undisclosed amount | |
| Jul 27, 2001 | Undisclosed amount | |
| May 19, 2001 | Undisclosed amount | |
| Sep 05, 2000 | Undisclosed amount | |
| Sep 02, 2000 | Undisclosed amount | |
| Jan 19, 2000 | $ 162,000,000,000 | |
| Dec 22, 1999 | Undisclosed amount | |
| Jun 01, 1999 | Undisclosed amount | |
| May 01, 1999 | $ 388,000,000 | |
| Nov 28, 1998 | Undisclosed amount | |
| Jun 08, 1998 | $ 287,000,000 | |
| Jan 26, 1998 | Undisclosed amount | |
| Nov 10, 1997 | Undisclosed amount | |
| Nov 25, 1996 | Undisclosed amount | |
| Aug 06, 1996 | Undisclosed amount | |
| Feb 01, 1996 | Undisclosed amount | |
| May 23, 1995 | $ 30,900,000 | |
| Dec 01, 1994 | Undisclosed amount | |
| Dec 01, 1994 | Undisclosed amount |