You can't argue that the gap isn't growing from a pure resources perspective (looking at expenditures) and it becomes even more obvious when you see the advantages that the P5 have in terms of facilities. Maybe the P5 are doing less with more and the non-P5 are doing more with less?

Another consideration is that the 'average' doesn't capture the full picture. The gap between a mid to lower tier P5 program and a non-P5 program likely hasn't grown significantly, but I'd expect to see the gap growing among the top tier P5 programs against everyone else.

What does this stat look like if you cut it based on quartiles of expenditures?