In 1946, the US government published the Strategic Bombing Survey.  Here is a link to the Pacific volume online.
http://www.anesi.com/ussbs01.htmNote that the SBS claims that over 60% of all shot down American aircraft in the Pacific in WW2 were shot down by ground fire.  There were over 8700 planes lost.  That puts the ack kill number at more than 5200.
I am trying to do a comparison with the stats provided by AH, but i don't know if the data is complete.  I don't know if robo-ack shootdowns are included in the stats.  Could Skuzzy or somebody let me know?
Here's the info for the F4U-1D, a 'typical'  Pacific Jabo:
F4U-1D has 9117 Kills of All models 
All models have 10395 Kills of F4U-1D 
Kills by                                       Qty
Ostwind                                    967
Ship Gunner                              605
LVTA2                                        12
LVTA4                                        10
PzKpfw. IV                                270
M16MGMC                                 277
M3                                              50
M8                                              26
PT Boat                                     366
TOTAL                                      2583
24.8% of total kills of F4U-1Ds
If these are the grand total--if field robo ack and ship robo ack are included in the data presented-- the numbers don't match reality.  We should stop kvetching about the ack being too powerful.  If the info is not complete, that is of course invalid. 
Thoughts?  Comments??