In Lok Sabha Q & A session, Shri Kesineni Nani asked with a unstarred question no. 5478 to Shree Manoj Sinha, Ministry of State (IC) of the Ministry of Communication & Ministry of State in the Ministry of Railway on 28th March, 2018. Here is question answer listed below..
Source : https://aipeugdsnfpe.blogspot.in/2018/03/revenue-earned-by-post-offices-from.html?m=1
Here is another Q&A of Lok Sabha