entergy mississippi may refinance , redeem , or otherwise retire debt and preferred stock prior to maturity , to the extent market conditions and interest and dividend rates are favorable . all debt and common and preferred stock issuances by entergy mississippi require prior regulatory approval . a0 a0preferred stock and debt issuances are also subject to issuance tests set forth in its corporate charter , bond indenture , and other agreements . a0 a0entergy mississippi has sufficient capacity under these tests to meet its foreseeable capital needs . entergy mississippi 2019s receivables from the money pool were as follows as of december 31 for each of the following years. .
not including letters from the uncommitted facility , what percent of the borrowings allowance do the letters of credits set to expire may 2018 amount to?
see note 4 to the financial statements for a description of the money pool . entergy mississippi has four separate credit facilities in the aggregate amount of $ 102.5 million scheduled to expire may 2018 . no borrowings were outstanding under the credit facilities as of december a031 , 2017 . a0 a0in addition , entergy mississippi is a party to an uncommitted letter of credit facility as a means to post collateral to support its obligations to miso . as of december a031 , 2017 , a $ 15.3 million letter of credit was outstanding under entergy mississippi 2019s uncommitted letter of credit facility . see note 4 to the financial statements for additional discussion of the credit facilities . entergy mississippi obtained authorizations from the ferc through october 2019 for short-term borrowings not to exceed an aggregate amount of $ 175 million at any time outstanding and long-term borrowings and security issuances . see note 4 to the financial statements for further discussion of entergy mississippi 2019s short-term borrowing limits . entergy mississippi , inc . management 2019s financial discussion and analysis state and local rate regulation and fuel-cost recovery the rates that entergy mississippi charges for electricity significantly influence its financial position , results of operations , and liquidity . entergy mississippi is regulated and the rates charged to its customers are determined in regulatory proceedings . a governmental agency , the mpsc , is primarily responsible for approval of the rates charged to customers . formula rate plan in march 2016 , entergy mississippi submitted its formula rate plan 2016 test year filing showing entergy mississippi 2019s projected earned return for the 2016 calendar year to be below the formula rate plan bandwidth . the filing showed a $ 32.6 million rate increase was necessary to reset entergy mississippi 2019s earned return on common equity to the specified point of adjustment of 9.96% ( 9.96 % ) , within the formula rate plan bandwidth . in june 2016 the mpsc approved entergy mississippi 2019s joint stipulation with the mississippi public utilities staff . the joint stipulation provided for a total revenue increase of $ 23.7 million . the revenue increase includes a $ 19.4 million increase through the formula rate plan , resulting in a return on common equity point of adjustment of 10.07% ( 10.07 % ) . the revenue increase also includes $ 4.3 million in incremental ad valorem tax expenses to be collected through an updated ad valorem tax adjustment rider . the revenue increase and ad valorem tax adjustment rider were effective with the july 2016 bills . in march 2017 , entergy mississippi submitted its formula rate plan 2017 test year filing and 2016 look-back filing showing entergy mississippi 2019s earned return for the historical 2016 calendar year and projected earned return for the 2017 calendar year to be within the formula rate plan bandwidth , resulting in no change in rates . in june 2017 , entergy mississippi and the mississippi public utilities staff entered into a stipulation that confirmed that entergy .