The Our World in Data post, The rise of living alone: how one-person households are becoming increasingly common around the world by Esteban Oritz-Ospina (12/10/2019), provides the chart copied here.
National income per capita and the share of one-person households are strongly correlated…
These correlations are partly due to the fact that people who can afford to, often choose to live alone. Indeed, rising incomes in many countries are likely part of the reason why people are more likely to live alone today than in the past.
But there must be more to it since even at the same level of incomes there are clear differences between regions. In particular, Asian countries have systematically fewer one-person households than African countries with comparable GDP levels.
The article contains two other charts and data.