| Company | Ranking | Outlook | Date |
|---|---|---|---|
| Moody’s | Baa1 | Unfavorable | Jan 31 2023 |
| S&P | BBB | Unfavorable | Dec 12 2022 |
| S&P | BBB | Secure | Mar 18 2022 |
| S&P | BBB+ | Unfavorable | Oct 18 2021 |
| Moody’s | Baa1 | Secure | Sep 01 2021 |
| Moody’s | A3 | Unfavorable | Could 21 2021 |
| DBRS | N/A | N/A | Apr 04 2017 |
| Moody’s | A3 | Secure | Jul 02 2014 |
| DBRS | BBB (excessive) | Secure | Could 30 2014 |
| S&P | BBB+ | Secure | Aug 19 2013 |
| DBRS | BBB | Optimistic | Apr 29 2013 |
| S&P | BBB | Optimistic | Aug 28 2012 |
| Moody’s | Baa2 | Optimistic | Aug 16 2012 |
| DBRS | BBB (low) | Optimistic | Feb 23 2012 |
| S&P | BBB | Secure | Aug 30 2011 |
| Moody’s | Baa3 | Optimistic | Mar 21 2011 |
| S&P | BBB- | Optimistic | Aug 23 2010 |
| Moody’s | Baa3 | Secure | Dec 16 2009 |
| Moody’s | Ba1 | Optimistic Watch | Sep 29 2009 |
| Moody’s | Ba1 | Secure | Aug 19 2008 |
| S&P | BBB- | Secure | Jul 14 2008 |
| DBRS | BBB (low) | Secure | Oct 19 2007 |
| S&P | BB+ | Optimistic | Jul 23 2007 |
| Moody’s | Ba2 | Secure | Jul 16 2007 |
| Moody’s | Ba3 | Optimistic Watch | Mar 08 2007 |
| S&P | BB+ | Secure | Nov 20 2006 |
| Moody’s | Ba3 | Optimistic | Nov 07 2006 |
| S&P | BB | Optimistic | Jul 11 2005 |
| S&P | BB | Secure | Jun 08 2004 |
| S&P | BB- | Secure | Jul 02 2002 |
| S&P | BB- | Optimistic | Jan 24 2002 |
| S&P | BB- | Secure | Nov 01 2000 |
| S&P | BB | Unfavorable | Sep 19 2000 |
| S&P | BB | Secure | Jun 16 2000 |
| S&P | BB | Unfavorable Watch | Could 19 2000 |
| Moody’s | Ba3 | Secure | Mar 27 1998 |
| Moody’s | B2 | Optimistic Watch | Feb 13 1998 |
| S&P | BB | Secure | Dec 18 1997 |
| Moody’s | B2 | Secure | Feb 05 1996 |
