Hi, keep in mind that the Percent as it's showing in the Workspace is based on the row number divided by the "total", and you are looking at Visitors (which would show the same users in each row of the report).
Your Total Visitors in your example are 5260 Visitors, and the "Scroll Less than 25%" is 5258 Visitors (5258 / 5260 rounds to 100%)
Your "scroll percentage" is a page based metric.. each page will record individually, but you are paring with a Visitor metric.. so odds are, most visitors hit at least one page where they scrolled less than 25%...
You might be better off looking at Max Scroll Depth by Pages, not by Visitor to get the percentage of pages by scroll depth.