| Company | Score | Outlook | Date |
|---|---|---|---|
| Fitch | AA- | Unfavourable | Oct 05 2022 |
| S&P | AA | Unfavourable | Sep 30 2022 |
| Fitch | AA- | Secure | Jun 18 2021 |
| DBRS | AA (excessive) | Secure | Nov 13 2020 |
| Moody’s | Aa3 | Secure | Oct 16 2020 |
| DBRS | AAA | Unfavourable | Might 15 2020 |
| Fitch | AA- | Unfavourable | Mar 27 2020 |
| Fitch | AA | Unfavourable | Dec 17 2019 |
| S&P | AA | Secure | Dec 17 2019 |
| Moody’s | Aa2 | Unfavourable | Nov 08 2019 |
| Fitch | AA | Unfavourable Watch | Feb 20 2019 |
| Moody’s | Aa2 | Secure | Sep 22 2017 |
| Fitch | AA | Unfavourable | Jun 28 2016 |
| S&P | AA | Unfavourable | Jun 27 2016 |
| Moody’s | Aa1 | Unfavourable | Jun 24 2016 |
| S&P | AAA | Unfavourable | Jun 12 2015 |
| S&P | AAA | Secure | Jun 13 2014 |
| Fitch | AA+ | Secure | Apr 19 2013 |
| Moody’s | Aa1 | Secure | Feb 22 2013 |
| S&P | AAA | Unfavourable | Dec 13 2012 |
| Fitch | AAA | Unfavourable | Mar 14 2012 |
| Moody’s | Aaa | Unfavourable | Feb 13 2012 |
| S&P | AAA | Secure | Oct 26 2010 |
| DBRS | AAA | Secure | Jul 19 2010 |
| S&P | AAA | Unfavourable | Might 21 2009 |
| Fitch | AAA | Secure | Sep 21 2000 |
| Fitch | AAA | Secure | Sep 21 2000 |
| Fitch | AAA | N/A | Aug 10 1994 |
| S&P | AAA | Secure | Jun 26 1989 |
| S&P | AAA | N/A | Apr 28 1978 |
| Moody’s | Aaa | Secure | Mar 31 1978 |
