| Company | Ranking | Outlook | Date |
|---|---|---|---|
| Fitch | BBB- | Secure | Dec 15 2021 |
| DBRS | BBB (low) | Optimistic | Nov 24 2021 |
| Fitch | BBB- | Unfavourable | Oct 05 2018 |
| Moody’s | Baa2 | Secure | Jul 13 2017 |
| S&P | BBB | Secure | Could 30 2017 |
| Moody’s | Baa2 | Unfavourable | Jun 22 2016 |
| S&P | BBB | Unfavourable | Jun 06 2016 |
| S&P | BBB | Secure | Jun 05 2015 |
| Moody’s | Baa2 | Secure | Could 29 2014 |
| DBRS | BBB (low) | Secure | Could 03 2013 |
| Fitch | BBB- | Secure | Mar 07 2013 |
| Moody’s | Baa3 | Optimistic | Jul 31 2012 |
| Fitch | BB+ | Optimistic | Apr 24 2012 |
| DBRS | BB (excessive) | Optimistic | Apr 04 2012 |
| S&P | BBB- | Secure | Apr 03 2012 |
| Moody’s | Ba1 | Optimistic | Jan 26 2012 |
| S&P | BB+ | Secure | Jul 25 2011 |
| Fitch | BB+ | Secure | Jul 14 2011 |
| DBRS | BB | Optimistic | Feb 15 2011 |
| Moody’s | Ba1 | Secure | Dec 08 2010 |
| Fitch | BB | Optimistic | Jul 27 2010 |
| Moody’s | Ba3 | Optimistic Watch | Jul 15 2010 |
| DBRS | BB | Secure | Apr 08 2010 |
| DBRS | BB (low) | Optimistic | Sep 21 2009 |
| Fitch | BB- | Optimistic | Jul 13 2009 |
| Moody’s | Ba3 | Secure | Jan 12 2009 |
| Moody’s | B1 | Optimistic Watch | Aug 14 2008 |
| DBRS | BB (low) | Secure | Feb 28 2008 |
| Fitch | BB- | Secure | Jul 27 2007 |
| Moody’s | B1 | Secure | Dec 21 2006 |
| Moody’s | B3 | Optimistic Watch | Sep 12 2006 |
| Fitch | B+ | Optimistic | Could 24 2006 |
| Fitch | B+ | Secure | Mar 07 2005 |
| Moody’s | B3 | Secure | Nov 10 2004 |
| Fitch | B | Secure | Mar 29 2004 |
| Fitch | B- | Secure | Jun 17 2003 |
| Fitch | DDD | N/A | Could 16 2003 |
| Fitch | C | N/A | Apr 10 2003 |
| Fitch | CCC- | Unfavourable | Mar 12 2003 |
| Fitch | B- | Unfavourable | Jan 07 2003 |
| Moody’s | B3 | Unfavourable | Jul 31 2002 |
| Fitch | B | Unfavourable | Jul 30 2002 |
| Moody’s | B1 | Unfavourable | Jul 10 2002 |
| Fitch | B+ | Unfavourable Watch | Could 28 2002 |
| Moody’s | Ba2 | Unfavourable Watch | Could 21 2002 |
| Moody’s | Ba2 | Unfavourable | Could 03 2002 |
| Moody’s | Baa3 | Unfavourable Watch | Apr 04 2002 |
| Fitch | BB+ | Unfavourable | Mar 13 2002 |
| Moody’s | Baa3 | Unfavourable | Feb 19 2002 |
| Fitch | BBB- | Unfavourable | Jul 23 2001 |
| Fitch | BBB- | Secure | Sep 21 2000 |
| Moody’s | Baa3 | Secure | Jun 10 1997 |
| Fitch | BBB- | N/A | Jan 23 1997 |
| Fitch | BB+ | Optimistic Watch | Jan 14 1997 |
| Fitch | BB+ | N/A | Jan 18 1995 |
| Moody’s | Ba1 | Secure | Oct 15 1993 |
