pre_text: The credit quality and credit concentration of cash equivalents, current asset investments and derivative financial assets are detailed in the tables below. Where the opinion of Moody’s and Standard & Poor’s (S&P) differ, the lower rating is used. a We hold cash collateral of £638m (2017/18: £492m, 2016/17: £702m) in respect of derivative financial assets with certain counterparties. The concentration of credit risk for our trading balances is provided in note 17, which analyses outstanding balances by customerfacing unit. Where multiple transactions are undertaken with a single financial counterparty or group of related counterparties, we enter into netting arrangements to reduce our exposure to credit risk by making use of standard International Swaps and Derivatives Association (ISDA) documentation. We have also entered into credit support agreements with certain swap counterparties whereby, on a daily, weekly and monthly basis, the fair value position on notional £3,289m of long dated cross-currency swaps and interest rate swaps is collateralised. The related net cash inflow during the year was £129m (2017/18: outflow £220m, 2016/17: inflow £100m). The collateral paid and received is recognised within current asset investments and loans and other borrowings, respectively.
table: 2019 2018 2017
table: Moody’s / S&P credit rating of counterparty £m £m £m
table: Aa2/AA and above 2,522 2,575 1,444
table: Aa3/AA– 1,376 313 208
table: A1/A+a 1,145 651 952
table: A2/Aa 649 628 370
table: A3/A–a 50 180 204
table: Baa1/BBB+a 75 59 561
table: Baa2/BBB and below a 160 207 86
table: 5,977 4,613 3,825
question: Analyse this data from a financial earnings document. What is the average Aa3/AA– for 2017-2019?