How to calculate a profit figure for the quarter or for the year?
You don't need to look at that site. On the bitdice website, you can instantly see how much profit they have made with each coin. After logging in, go to the homepage, click on games -> dice, and in the top right corner it will show how much profit has been made so far since the tokens have been distributed. At this point, it is 7.17 BTC, 136 LTC, 2.6M DOGE and 10 ETH.
Is there not the correct data on the website https://dicesites.com/bitdiceme?
I am not sure if the date from dicesites.com is for dice only, or for both blackjack, dice etc. What I do know for sure, is that the amount of profit shown on the website (what I mentioned in my previous post), is for all the games together. That is what you need to know, because that is the amount that the site will be paying out to their investors.