hrreport: Visually distinguish statistic options

When creating a new report based on the CiviHR Summary template, there are a number of checkboxes under the headings of "Display Columns: Stats and Work Fields". The stats fields should stand out as quite distinct from the other fields. The stats fields are:

-People
-Job Positions
-Full Time Equivalents
-Annual Cost Equivalents
-Monthly Cost Equivalents

Ideally, the stats fields would be listed under a separate heading (ie "Statistics").

If doing this is particularly challenge, then it would help to explain why. We might consider alternatives – such as displaying the each statistic in bold or with a different font color. The main goal – it should immediately obvious which fields are useful for grouping and which fields provide the stats.