management 2019s discussion and analysis of financial condition and results of operations ( continued ) detail with respect to our investment portfolio as of december 31 , 2014 and 2013 is provided in note 3 to the consolidated financial statements included under item 8 of this form 10-k . loans and leases averaged $ 15.91 billion for the year ended 2014 , up from $ 13.78 billion in 2013 . the increase was mainly related to mutual fund lending and our continued investment in senior secured bank loans . mutual fund lending and senior secured bank loans averaged approximately $ 9.12 billion and $ 1.40 billion , respectively , for the year ended december 31 , 2014 compared to $ 8.16 billion and $ 170 million for the year ended december 31 , 2013 , respectively . average loans and leases also include short- duration advances . table 13 : u.s . and non-u.s . short-duration advances years ended december 31 .

2014: average u.s . short-duration advances: 2355
average non-u.s . short-duration advances: 1512
average total short-duration advances: 3867
average short-durance advances to average loans and leases: -24
2013: average u.s . short-duration advances: 2356
average non-u.s . short-duration advances: 1393
average total short-duration advances: 3749
average short-durance advances to average loans and leases: -27
2012: average u.s . short-duration advances: 1972
average non-u.s . short-duration advances: 1393
average total short-duration advances: 3365
average short-durance advances to average loans and leases: -29

average u.s . short-duration advances $ 2355 $ 2356 $ 1972 average non-u.s . short-duration advances 1512 1393 1393 average total short-duration advances $ 3867 $ 3749 $ 3365 average short-durance advances to average loans and leases 24% ( 24 % ) 27% ( 27 % ) 29% ( 29 % ) the decline in proportion of the average daily short-duration advances to average loans and leases is primarily due to growth in the other segments of the loan and lease portfolio . short-duration advances provide liquidity to clients in support of their investment activities . although average short-duration advances for the year ended december 31 , 2014 increased compared to the year ended december 31 , 2013 , such average advances remained low relative to historical levels , mainly the result of clients continuing to hold higher levels of liquidity . average other interest-earning assets increased to $ 15.94 billion for the year ended december 31 , 2014 from $ 11.16 billion for the year ended december 31 , 2013 . the increased levels were primarily the result of higher levels of cash collateral provided in connection with our enhanced custody business . aggregate average interest-bearing deposits increased to $ 130.30 billion for the year ended december 31 , 2014 from $ 109.25 billion for year ended 2013 . the higher levels were primarily the result of increases in both u.s . and non-u.s . transaction accounts and time deposits . future transaction account levels will be influenced by the underlying asset servicing business , as well as market conditions , including the general levels of u.s . and non-u.s . interest rates . average other short-term borrowings increased to $ 4.18 billion for the year ended december 31 , 2014 from $ 3.79 billion for the year ended 2013 . the increase was the result of a higher level of client demand for our commercial paper . the decline in rates paid from 1.6% ( 1.6 % ) in 2013 to 0.1% ( 0.1 % ) in 2014 resulted from a reclassification of certain derivative contracts that hedge our interest-rate risk on certain assets and liabilities , which reduced interest revenue and interest expense . average long-term debt increased to $ 9.31 billion for the year ended december 31 , 2014 from $ 8.42 billion for the year ended december 31 , 2013 . the increase primarily reflected the issuance of $ 1.5 billion of senior and subordinated debt in may 2013 , $ 1.0 billion of senior debt issued in november 2013 , and $ 1.0 billion of senior debt issued in december 2014 . this is partially offset by the maturities of $ 500 million of senior debt in may 2014 and $ 250 million of senior debt in march 2014 . average other interest-bearing liabilities increased to $ 7.35 billion for the year ended december 31 , 2014 from $ 6.46 billion for the year ended december 31 , 2013 , primarily the result of higher levels of cash collateral received from clients in connection with our enhanced custody business . several factors could affect future levels of our net interest revenue and margin , including the mix of client liabilities ; actions of various central banks ; changes in u.s . and non-u.s . interest rates ; changes in the various yield curves around the world ; revised or proposed regulatory capital or liquidity standards , or interpretations of those standards ; the amount of discount accretion generated by the former conduit securities that remain in our investment securities portfolio ; and the yields earned on securities purchased compared to the yields earned on securities sold or matured . based on market conditions and other factors , we continue to reinvest the majority of the proceeds from pay-downs and maturities of investment securities in highly-rated securities , such as u.s . treasury and agency securities , municipal securities , federal agency mortgage-backed securities and u.s . and non-u.s . mortgage- and asset-backed securities . the pace at which we continue to reinvest and the types of investment securities purchased will depend on the impact of market conditions and other factors over time . we expect these factors and the levels of global interest rates to influence what effect our reinvestment program will have on future levels of our net interest revenue and net interest margin. .

Questions:
what was the loan amount in 2014, in millions?
and what was it in 2013, also in millions?
what was, then, the change over the year?
and how much does that change represent in relation to the loan amount in 2013, in percentage?

Answers:
15.91
13.78
2.13
15.5%