28 \ Global Youth Development Index and Report 2016 Highlights (continued) the Commonwealth live in countries that are in the low and medium YDI categories. – Gaps between low and very high YDI countries are most pronounced in the access that young people have to education, health services, financial inclusion and digital technology. Within the youth cohort in low YDI countries, young females are much less likely to have these opportunities than their male peers. – In a few areas of youth development, the scores for countries in the higher YDI categories are the same or even worse than those for countries in the lower YDI categories: youth-to-adult unemployment ratio, mental disorder and drug abuse. • Youth development tends to be highest in countries where young people represent a relatively small share of the population. Among the ten highestranked countries in the YDI, only one country – Australia – has a youth cohort that represents more than 20 per cent of the total population. In contrast, young people make up more than 25 per cent of the total population in nearly all the 30 lowest-ranked countries. • South Asia, Central America and Caribbean, and Asia-Pacific score better on youth development than their overall level of human development. The MENA region, Russia and Eurasia, North America and Sub-Saharan Africa have higher levels of overall human development than youth development, suggesting that the development of young people trails that of other age cohorts in the countries of these regions. • Traditional indicators of development, such as governance and income, remain important predictors or proxies of youth development. Only three countries in the YDI top 30 – Costa Rica, Chile and Latvia – are not in the highincome category.