The graph is from this paper by Anton I. Badev, Thorsten Beck, Ligia Vado, & Simon C. Walley. The title is "Housing Finance Across Countries: New Data and Analysis."
This paper presents new data on the depth and penetration of mortgage markets across countries. There is a large variation across both dimensions of mortgage market development, across countries, but also -- in terms of depth -- within countries. Mortgage markets seem to develop only at relatively high levels of gross domestic product per capita. Policies associated with financial system development are also associated with mortgage market development, including price stability and the efficiency of contractual and information frameworks. The development of the insurance sector and the stock market, sources of long-term funding, is strongly associated with mortgage market development, while government subsidies and support are not. A benchmarking exercise compares the actual values of mortgage market development to values predicted by structural country factors and shows a large variation across countries and over time in the gap between predicted and actual values, related to specific policies but also mortgage boom and bust cycles.
The authors argue that mortgage markets seem to be "luxury goods." Probably the most important finding in the article is that government subsidies are not associated with the development of mortgage markets.
Can you see where Guatemala is in the graph?