| Date | Acquired | Amount |
|---|---|---|
| Nov 30, 2016 | $ 1,420,000,000 | |
| Apr 04, 2016 | $ 18,900,000 | |
| Nov 23, 2015 | CA$ 465,000,000 | |
| Nov 10, 2015 | € 95,000,000 | |
| Jan 14, 2015 | $ 675,000,000 | |
| Apr 28, 2014 | Undisclosed amount | |
| Oct 07, 2013 | Undisclosed amount | |
| Aug 19, 2013 | Undisclosed amount | |
| Dec 14, 2012 | Undisclosed amount | |
| Oct 17, 2012 | Undisclosed amount | |
| Oct 01, 2012 | Undisclosed amount | |
| Jun 05, 2012 | Undisclosed amount | |
| May 01, 2012 | Undisclosed amount | |
| Mar 19, 2012 | $ 2,300,000,000 | |
| Jan 01, 2012 | Undisclosed amount | |
| Oct 01, 2011 | Undisclosed amount | |
| Sep 01, 2010 | Undisclosed amount | |
| Jun 01, 2010 | Undisclosed amount | |
| Mar 01, 2010 | Undisclosed amount | |
| May 01, 2009 | Undisclosed amount | |
| Feb 01, 2009 | Undisclosed amount | |
| Sep 01, 2008 | Undisclosed amount | |
| Aug 01, 2008 | Undisclosed amount | |
| Jul 01, 2008 | Undisclosed amount | |
| Feb 01, 2008 | Undisclosed amount | |
| Feb 01, 2008 | Undisclosed amount | |
| Nov 01, 2007 | Undisclosed amount | |
| Nov 01, 2007 | Undisclosed amount | |
| Oct 01, 2007 | Undisclosed amount | |
| Oct 01, 2007 | Undisclosed amount | |
| Aug 01, 2007 | Undisclosed amount |