| Date | Acquired | Amount |
|---|---|---|
| Oct 05, 2016 | Undisclosed amount | |
| Jul 14, 2016 | Undisclosed amount | |
| Jul 11, 2016 | Undisclosed amount | |
| May 24, 2016 | $ 165,000,000 | |
| May 05, 2016 | Undisclosed amount | |
| Mar 30, 2016 | Undisclosed amount | |
| Jul 20, 2015 | Undisclosed amount | |
| Oct 01, 2014 | Undisclosed amount | |
| Feb 20, 2014 | Undisclosed amount | |
| Oct 22, 2013 | Undisclosed amount | |
| Sep 27, 2013 | Undisclosed amount | |
| Sep 06, 2013 | Undisclosed amount | |
| Jul 04, 2013 | Undisclosed amount | |
| Jul 04, 2013 | Undisclosed amount | |
| Sep 06, 2012 | Undisclosed amount | |
| Feb 23, 2012 | Undisclosed amount | |
| Dec 22, 2011 | Undisclosed amount | |
| Nov 21, 2011 | $ 80,000,000 | |
| Sep 07, 2011 | Undisclosed amount | |
| Jul 12, 2011 | Undisclosed amount | |
| Jul 07, 2011 | $ 240,000,000 | |
| Jun 20, 2011 | $ 2,400,000,000 | |
| Jun 06, 2011 | $ 180,000,000 | |
| May 02, 2011 | Undisclosed amount | |
| Apr 20, 2011 | $ 135,000,000 | |
| Apr 12, 2011 | Undisclosed amount | |
| Dec 20, 2010 | Undisclosed amount | |
| Dec 02, 2010 | Undisclosed amount | |
| Jun 23, 2010 | Undisclosed amount | |
| Jan 08, 2009 | Undisclosed amount | |
| Oct 06, 2008 | Undisclosed amount | |
| Oct 06, 2008 | $ 945,000,000 | |
| Aug 13, 2008 | Undisclosed amount | |
| May 02, 2008 | Undisclosed amount | |
| Oct 04, 2007 | Undisclosed amount | |
| May 30, 2007 | $ 75,000,000 | |
| May 19, 2007 | Undisclosed amount | |
| Mar 30, 2007 | Undisclosed amount | |
| Jan 10, 2007 | $ 310,000,000 | |
| Apr 24, 2006 | $ 48,300,000 | |
| Sep 12, 2005 | $ 2,600,000,000 | |
| Jun 02, 2005 | Undisclosed amount | |
| May 18, 2005 | Undisclosed amount | |
| Jan 13, 2005 | Undisclosed amount | |
| Dec 17, 2004 | $ 415,000,000 | |
| Nov 10, 2004 | Undisclosed amount | |
| Jun 23, 2004 | Undisclosed amount | |
| Jan 27, 2004 | Undisclosed amount | |
| Jul 16, 2003 | Undisclosed amount | |
| Jan 31, 2003 | Undisclosed amount | |
| Jul 08, 2002 | $ 1,500,000,000 | |
| Feb 22, 2001 | $ 100,000,000 | |
| Jan 15, 2001 | Undisclosed amount | |
| Jun 13, 2000 | $ 350,000,000 | |
| Jun 22, 1999 | Undisclosed amount | |
| May 18, 1999 | Undisclosed amount | |
| Apr 26, 1999 | Undisclosed amount | |
| Jul 16, 1998 | Undisclosed amount |