BBC News By Clodagh Rice Published image copyrightGetty Images Northern Ireland firms increased their prices last month at the highest rate since 2018, according to an Ulster Bank survey. It says firms saw their costs rise at the highest rate in the UK, largely as a result of higher shipping costs. Every month the bank asks firms across the private sector about things to determine their economic performance. Staffing levels, new orders and exports are considered to be reliable indicators. Ulster Bank's Chief Economist in Northern Ireland Richard Ramsey said: "Northern Ireland's firms signalled the highest rate of input cost inflation across the UK with input prices rising at the fastest rate since June 2018."