Underlying earnings at the Reserve Bank of Australia in the year to June 2013 were A$700 million, about the same as the previous year and "very low by historical standards", the bank said in its annual report, which was released yesterday. The RBA said the low earnings "mainly reflect the very low level of interest rates, especially those in the major advanced countries where the bank holds its foreign assets."Its accounting profit, which recognises realised and unrealised valuation changes, was $4.3 billion, the highest for four years. Earnings available for distribution were $588 million, down from $1.1 billion.The Reserve Bank said its cost of operations increased by eight per cent in 2012/13. It said: "Some cost increases in the business areas were matched by revenue gains, but stripping those out, operating costs rose by about 6.5 per cent."A heavy investment program explains the rise in costs, to cater to the "next generation" bank note project, the New Payments Platform, and an upgrade of the Reserve Bank's banking systems.The RBA said its "current systems have been operating for nearly two decades and, while still reliable, are nearing the end of their useful life. Use of more modern technology will better meet customer needs, improve efficiency and reduce operational risks in the bank."