For the statistics published at midnight, display will change a little bit.
There will be 3 leaderboards, presenting each the best 25 curators in the last 7 days, but each leaderboard will only contain curators having casted a certain value, as the curation game changes when you need some VP/SP management and need to diversify your votes.
Also, you'll need to have casted at least 3500% in upvote strength in that time frame, in lawman terms, you'll need to have used at least 50% of the available Voting Power in the time frame.