SB 3.11.21
dharmas catus-pan manujan
krte samanuvartate
sa evanyesv adharmena
vyeti padena vardhata
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O Vidura, in the Satya millennium mankind properly and completely maintained the principles of religion, but in other millenniums religion gradually decreased by one part as irreligion was proportionately admitted.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In the Satya millennium, complete execution of religious principles prevailed. Gradually, the principles of religion decreased by one part in each of the subsequent millenniums. In other words, at present there is one part religion and three parts irreligion. Therefore people in this age are not very happy.