The Tidewater State Bank has $1000 in total assets (all of which are earning assets), $700 of which will be replaced with in the next 90 days. This bank also has $800 in total liabilities, $400 of which will be replaced within the next 90 days. Currently, the bank is earning 8% on its assets and is paying 5% on its liabilities. If interest rates do not change in the next ninety days, what is this bank's net interest margin?