The following entries (in millions of dollars) are from the balance sheet of Rivendell National Bank (RNB): U.S. Treasury bills Demand deposits Mortgage-backed securities Loans from other banks C&I loans Discount loans NOW accounts Savings accounts Reserve deposits with Federal Reserve Cash items in the process of collection Municipal bonds Bank building $18 $44 $33 $6 $55 $7 $40 $10 $9 $7 $5 $3 If RNB's assets have an average duration of five years and its liabilities have an average duration of four years, what is RNB's duration gap? Duration gap