It isn't coming from my own personal experience it's coming from the facts of the report. The report specifically states that parents are eighty percent of the cases of neglect, abuse and fatalities, twenty percent come from other sources, which foster care falls under.

Therefore, and once again, using the example you provided that would mean this:

If there were equal amounts of kids in foster care and under parental care then eighty percent of children in parental care would be harmed and less than twenty percent of children in foster would be harmed as foster care encompassed a fraction of that twenty percent.

Like I said you can twist it anyway you want, go find reports from all sorts of bias organization trying to contort figures in their favor but the fact is these stats provided are a result of the demand by these same people for accurate according of what is happening with kids, these stats or reports are scrutinized by media and are easily confirmed if media goes back and looks at how baby john doe died because these stories made headlines. Now I am now done with your contorting of this issue. Have a nice day.