By my count, I'm seeing PHX has gotten 9 new bodies since 2017, 7 of which were hardships, 1 ERR that was just selected in the November '21 panel, and a previous experience new hire that gets there next week. For P50 since late 2015, we have 32 new bodies with 5 previous experience, 1 NEST, 18 hardships, and 8 ERR's.
As far as places with the most hardships into them, just by eyeballing the data here, I've found
RDU: 12
RSW: 8
SCT: 9
SLC: 8
BNA: 8
CLT: 8
DAL: 7
DEN: 5 (surprisingly low considering the running jokes)
F11: 13
HOU: 9
IAH: 5
IND: 6
JAX: 8
OKC: 7
P31: 6
P80: 6
PBI: 5
PDK: 6
PIT: 6
S46: 6
SEA: 5
SFB: 6
SLC: 8
TPA: 13
TUL: 5
As far as places with the most hardship outbounds, I didn't look thru them as hard but I counted 27 from ZOA and 14 from ZNY