Denmark's central government debt was 21 per cent of GDP at the end of 2017. This is a decrease from 2016, attributable to a government budget surplus. In 2017, on average, the central government issued bonds at a yield to maturity of 0.2 per cent and a maturity of 7.5 years. Interest costs for the central government debt totalled 0.8 per cent of GDP. The yield spread to Germany narrowed, and liquidity improved further in the market for Danish government bonds in 2017, where the central government introduced a new primary dealer model.