Ontario's share of the federal debt raises the debt-to-GDP ratio to 82%.

Other provinces have a debt-to-GDP ratio of 35%.

This should bring Greece's debt-to-GDP ratio down to 124% by 2020 and well below 110% two years later.

The debt-to-GDP ratio is however a lot worse than initially expected, as it is now predicted to reach 175.6% in 2012 and 189.1% in 2013.

Particularly in macroeconomics, various debt-to-GDP ratios can be calculated.

The debt-to-GDP ratio is generally expressed as a percentage, but properly has units of years, as below.

The leaders also agreed on reducing debt-to-GDP ratio in each economy by 2016.

The debt-to-GDP ratio, which was expected to peak at 70%, hit 75% in 2012, and is forecast to climb to 80% in 2015-2016.

Stronger growth would make it easier for governments to balance their books and reduce their debt-to-GDP ratios.

Italy has a debt-to-GDP ratio of 119pc, among the largest in the eurozone.