HDI stands for Human Development Index, and is a value that represents the average life expectancy, education, and per capita income, ranging from a 0 to a perfect 1.
No available data for Nauru, Tuvalu, North Korea, Kosovo, Taiwan, Monaco, Vatican City, San Marino, and Somalia.
Data taken from the UNDP 2020 National HDI Rankings
These regional groupings are strange. There's only one country labelled "Near East," "Eurasia" only applies to two countries and is less about their regional location than their transcontinental territory, Mauritania is labelled as "East Africa" which it is most certainly not, the Caucasus countries are labelled as "Central Asia" while every Armenian person I know describes themselves as (South)West Asian using the SWANA acronym, and so on. Any way you slice the world yourself is going to be controversial no matter what, so I recommend having a clue that is far more standardized and unarguable, such as the starting letter of the country or the UN geoscheme. https://en.wikipedia.org/wiki/United_Nations_geoscheme