By contrast, a 2/5  BIS central bankers' speeches  rise in the primary surplus by 1 percentage point of GDP lowers the debt-to-GDP ratio by only 1 percentage point (assuming that the fiscal multiplier is 0 which, as we well know, is not).
Now, the interest burden of Greek public debt is low until 2021 but increases substantially thereafter because of payments of deferred interest on the EFSF loans and interest on new debt issued in financial markets. An exercise done at the Bank looks at the impact of smoothing interest payments for EFSF loans over time.