Task Manager showing every process with 0% CPU usage

I suspect but don't know for sure that the number is being rounded and that the values are similar to those shown in the "Disk" column, i.e. they are less than 0.5 so they are not rounded up and there is no provision to show decimal percentages in the "CPU" column.

I'm not sure there is any fix for the problem.
 
Also: click the small upward or downward pointing "arrows" in the column headers to change the sort order.

Look in other Task Manager options and associated columns: App History, the Status Column and also at Details.

Status column - Check efficiency options.

Do not focus on just one column.

Use resource values vs percents. Right click a selected Process for more options.

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That all said: is there a particular problem or is it just a matter of curiousity?

Curiosity being valid.