Over the first two decades of the 21st century, more than two billion people lived in microregions that became blue, achieving life expectancy of more than 72.5 years and income greater than $8,300. In this chapter, we examine the development of the microregions they inhabit.

Overall, the global population living in blue microregions increased from 1.3 billion in 2000 to 3.5 billion in 2019, with microregions newly crossing the blue threshold driving most of the growth during that period. Microregions home to 2.0 billion surpassed the blue threshold, while microregions that were already blue in 2000 increased their population by an additional 0.2 billion.