Percentage decadal population growth rate (X₁): This is an important indicator of growth of population. Lower the decadal growth rate higher the index value and better the district. The decadal growth rate in Bihar increased from 23.4 percent (1991) to 28.4 per cent (2001). According to 2001, census findings decadal growth rate was recorded highest in Nagaland (64.4 per cent) and lowest in Kerala (9.4 per cent). Among all the districts Mamit district in Mizoram recorded the lowest (-3.49 per cent) percentage decadal growth rate while Wokha district in Nagaland recorded the highest growth rate (95.01 per cent). 

Index₁ = 100*(95.01-X₁)/(95.01-(-3.49)) 

          = 100*(95.01-X₁)/98.5