| Company | Ranking | Outlook | Date |
|---|---|---|---|
| Moody’s | A3 | Steady | Oct 02 2020 |
| DBRS | A (excessive) | Steady | Feb 21 2020 |
| DBRS | A | Constructive | Aug 30 2019 |
| Fitch | A | Steady | Jul 19 2019 |
| S&P | AA- | Steady | Jun 14 2019 |
| Moody’s | Baa1 | Constructive | Apr 26 2019 |
| S&P | A+ | Constructive | Jun 15 2018 |
| DBRS | A | Steady | Nov 17 2017 |
| Moody’s | Baa1 | Steady | Sep 08 2017 |
| S&P | A+ | Steady | Jun 16 2017 |
| S&P | A | Constructive | Dec 16 2016 |
| Fitch | A- | Steady | Sep 23 2016 |
| Moody’s | Baa3 | Constructive | Sep 16 2016 |
| S&P | A | Steady | Jun 17 2016 |
| Fitch | BBB+ | Constructive | Sep 25 2015 |
| S&P | A- | Constructive | Jun 19 2015 |
| Moody’s | Baa3 | Steady | Jan 23 2015 |
| S&P | A- | Steady | Dec 19 2014 |
| S&P | A- | Damaging | Jun 27 2014 |
| Fitch | BBB+ | Steady | Could 02 2014 |
| Moody’s | Ba1 | Steady | Jan 24 2014 |
| Fitch | BBB+ | Damaging | Could 17 2013 |
| Moody’s | Ba1 | Damaging | Apr 30 2013 |
| S&P | A- | Steady | Feb 12 2013 |
| S&P | A | Damaging Watch | Nov 06 2012 |
| Fitch | A- | Damaging | Aug 08 2012 |
| S&P | A | Damaging | Aug 03 2012 |
| Moody’s | Baa2 | Damaging | Aug 02 2012 |
| Moody’s | A2 | Damaging | Feb 13 2012 |
| Fitch | A | Damaging | Jan 27 2012 |
| S&P | A+ | Damaging | Jan 13 2012 |
| Moody’s | A1 | Damaging | Dec 22 2011 |
| Fitch | AA- | Damaging Watch | Dec 16 2011 |
| S&P | AA- | Damaging Watch | Dec 05 2011 |
| S&P | AA- | Steady | Oct 19 2011 |
| Fitch | AA- | Damaging | Sep 28 2011 |
| Moody’s | Aa3 | Damaging Watch | Sep 23 2011 |
| S&P | AA | Damaging | Dec 22 2010 |
| Moody’s | Aa2 | Steady | Mar 31 2009 |
| Moody’s | Aa2 | Constructive | Jul 26 2006 |
| Fitch | AA | Steady | Jul 12 2006 |
| Moody’s | Aa3 | Constructive Watch | Jun 07 2006 |
| S&P | AA | Steady | Could 16 2006 |
| Moody’s | Aa3 | Constructive | Mar 09 2006 |
| Fitch | AA- | Constructive | Jul 07 2004 |
| S&P | AA- | Steady | Could 13 2004 |
| Fitch | A+ | Constructive | Nov 04 2003 |
| Fitch | A+ | Steady | Could 06 2003 |
| S&P | A+ | Constructive | Mar 26 2003 |
| Moody’s | Aa3 | Steady | Nov 12 2002 |
| S&P | A | Constructive | Oct 23 2002 |
| Moody’s | A2 | Constructive | Aug 14 2002 |
| Fitch | A | Constructive | Could 29 2002 |
| Moody’s | A2 | Steady | Nov 14 2000 |
| Fitch | A | Steady | Sep 21 2000 |
| Moody’s | A3 | Constructive Watch | Sep 13 2000 |
| Fitch | A | N/A | Dec 15 1999 |
| Moody’s | A3 | Constructive | Sep 15 1999 |
| Fitch | A- | N/A | Could 09 1996 |
| S&P | A | Steady | Could 08 1996 |
| Moody’s | A3 | Steady | Could 08 1996 |
