What factors have driven up debt ratios in OECD countries?

Public debt and private debt can be substitutable: we therefore look at total debt in OECD countries. The total debt ratio in OECD countries , expressed as a percentage of GDP , increased sharply from 1999 to 2012. What caused this rise in debt in OECD countries? Abnormally expansionary monetary policy (abnormally low interest rates relative to growth)? The abnormally expansionary monetary policy may have resulted from the fall in the inflation risk; Central banks’ refusal to correct the rise in (financial and real estate) asset prices, which is related to the rise in debt? The rise in the return on equity on the back of the squeezing of wages, making the leverage effect more powerful? An overestimation of future growth? The first three explanations of the rise in the total debt ratio seem relevant .