2 the greater mekong subregion at 20 progress and prospects the increased prosperity and improved social well being of the gms are well reflected in the human development index hdi a comparative measure of life expectancy literacy education and standards of living table 2 hdi increased steadily in all gms countries between 1990 and. Over the past 20 years the greater mekong subregion program has achieved substantial success in improving regional connectivity through investments of 15 billion as well as more than 180 technical assistance projects. Over the past 20 years the greater mekong subregion program has achieved substantial success in improving regional connectivity through investments of 15 billion as well as more than 180 technical assistance projects. In 2012 the greater mekong sub region gms an initiative launched by the asian development bank adb to promote regional integration and development between six mainland southeast asian countries will reach its twentieth anniversary throughout the past