| Date Range |
Moody's Investors Service |
Standard and Poor's |
Fitch Ratings |
| May 2007 - Present |
A1 |
A+ |
A+ |
| November 2005 - May 2007 |
A2 (Positive Outlook) |
A+ |
A (Positive Outlook) |
| June 2005 - November 2005 |
A2 |
A |
A (Positive Outlook) |
|
November 2004 - June 2005 |
A2 |
A |
A- (Positive Outlook) |
|
April 2004 - November 2004 |
A2 |
A- |
A- |
| June 2003 - April 2004 |
Baa1 |
A- |
A- |
| March 2001 - June 2003 |
Baa1 |
BBB+ |
BBB+ |
| February 2001 - March 2001 |
Baa3 |
BBB+ |
BBB |
| June 1999 - February 2001 |
Baa3 |
BBB |
BBB |
| April 1999 - June 1999 |
Ba1 |
BBB |
BB+ |
| March 1998 - April 1999 |
Ba1 |
BB |
BB+ |
| May 1997 - March 1998 |
Ba2 |
B |
BB |
| April 1995 - May 1997 |
Ba |
B |
BB |
| February 1995 - April 1995 |
Ba |
BBB- |
BB |
| December 1994 - February 1995 |
Baa |
A- |
BBB+ |
| April 1993 - December 1994 |
Baa |
A- |
A- |
| May 1990 - April 1993 |
Baa |
A- |
No rating |
| November 1984 - May 1990 |
Baa |
A |
No rating |
