four-year, $5 billion share repurchase program approved by our Board of Directors in September 2008. Under that program, we purchased a total of 118.8 million shares at an average price of $42.08. Subsequently, we began repurchases under a four-year, $8 billion program approved by the Board in September 2012. As of the end of fiscal 2015, we had repurchased 80.9 million shares at an average price of $73.55 for a total cost of $5,950 million under this current program. We continue to expect funding of share repurchases will come from operating cash flow, excess cash and/or debt. The timing and the amount of shares purchased will be dictated by our capital needs and stock market conditions. 

Capital Resources 

On April 23, 2013, we filed a shelf registration statement (the “Shelf”) with the SEC which permits us to issue an unlimited amount of debt securities. The Shelf expires on April 23, 2016. On April 23, 2013, we issued $1.0 billion of senior notes with tranches maturing in 2023 and 2043. The 2023 senior notes were issued in an initial aggregate principal amount of $500 million at a 2.25% fixed, annual interest rate and will mature on May 1, 2023. The 2043 senior notes were issued in an initial aggregate principal amount of $500 million at a 3.625% fixed, annual interest rate and will mature on May 1, 2043. Interest on the senior notes is payable semi-annually on May 1 and November 1 of each year. The issuance resulted in gross proceeds before expenses of $998 million. 

On November 1, 2011, we entered into a committed credit facility agreement with a syndicate of banks which provides for up to $1 billion of borrowings with the option to increase borrowings to $1.5 billion with lender approval. The facility matures November 1, 2017. As of and for the periods ended May 31, 2015 and 2014, we had no amounts outstanding under our committed credit facility. 

We currently have long-term debt ratings of AA- and A1 from Standard and Poor’s Corporation and Moody’s Investor Services, respectively. If our long- term debt ratings were to decline, the facility fee and interest rate under our committed credit facility would increase. Conversely, if our long-term debt rating were to improve, the facility fee and interest rate would decrease. Changes in our long-term debt rating would not trigger acceleration of maturity of any then-outstanding borrowings or any future borrowings under the committed credit facility. Under this committed revolving credit facility, we have agreed to various covenants. These covenants include limits on our disposal of fixed assets, the amount of debt secured by liens we may incur, as well as a minimum capitalization ratio. In the event we were to have any borrowings outstanding under this facility and failed to meet any covenant, and were unable to obtain a waiver from a majority of the banks in the syndicate, any borrowings would become immediately due and payable. As of May 31, 2015, we were in full compliance with each of these covenants and believe it is unlikely we will fail to meet any of these covenants in the foreseeable future. 

Liquidity is also provided by our $1 billion commercial paper program. During the