Official figures show the eurozone's debt burden rose further in the second quarter despite years of austerity and a return to growth.

Eurostat, the EU's statistics office, says Wednesday that debt across the 17 countries that use the euro stood at 93.4 percent of the eurozone's annual gross domestic product, up from 92.3 percent the previous quarter.

Though countries across the region, such as Greece and Spain, have made great strides in reducing their borrowing through spending cuts and tax increases, they are still in deficit and that's adding to the stockpile of debt.

Greece remains the outlier. Its debt burden stood at 169.1 percent of GDP at the end of the second quarter, over 35 percentage points higher than the next most indebted country in the eurozone, Italy.