Figure 1 (Panel a) plots the aggregate private and public debt over time for 17 advanced economies since the late 19th century. Relative to GDP, total debt has more than doubled. Around the year 1900, the total debt of households, non-ﬁnancial businesses, and governments amounted to a little less than 100% of GDP.
In 2016, total debt was just about to cross the 200% mark. Advanced economies have levered up considerably during the past century, and a large share of the increase in total debt happened in the decades after 1970. Figure 1 (Panel b) also shows that there is considerable heterogeneity across advanced economies, reﬂecting different institutional structures, ﬁnancial sector regulation, social security systems, and preferences.