The question asks for the census year corresponding to the highest decadal growth rate among the choices. The decadal growth rates ending in these census years were: 1971 (1961-1971 decade): (1981-1991 decade): 23.87%, and 2001 (1991-2001 decade): 21.54%. The highest rate was recorded in the 1961-1971 decade, reported in the 1971 Census.