The 2 to 1 (B-17) and 1.8 to 1 (B-24) ratio of Luftwaffe claims to actual losses is exactly that, 2 Luftwaffe claims for every 1 B-17 the USAAF reports lost to fighters, 1.8 to 1 B-24.
David Osborne created a listing of B-17 histories and fates, FORTLOG.DOC which used to be available online and used in the book The B-17 Flying Fortress Story by Roger A. Freeman and David Osborne. Using that and other references like web sites and B-24 books a list of 8th Air Force heavy bomber losses was created, the B-17 are near complete the B-24 list is missing some, mostly combat write offs and non combat losses. This gives the heavy bomber losses on known combat sorties as
17 Aphrodite
390 Battle Damage
289 Collision
119 Crash
215 Flak & Fighter
1,893 Fighter
2,003 Flak
44 Friendly Fire
100 Fuel Starvation
1 Icing
130 Landing Accident
287 Mechanical Failure
57 On Ground (Poltava mostly)
96 Take off Accident
34 Taxi Accident
15 Unknown
5,690 Total, plus another 556 on non combat sorties
Ignoring the lost on ground and non combat sorties, losses come to 4,518 lost to combat (Aphrodite, battle damage, flak, fighter), 1,115 to non combat, total 5,633 with 14 losses on unknown type sorties excluded.
The USAAF Statistical Digest says on combat sorties, 2,452 lost to fighters, 2,439 to flak, 657 to other causes, total 5,548, or 85 less. 8th Air Force Heavy Bomber losses, percentage by cause, statistical digest figures.
Since the latest forum software update copying data in from a spreadsheet looks quite well while creating the message, then becomes a scrambled mess during the posting process, so a listing rather than tabulation.
In Sep-42, 100 Fighter, 0 Flak, 0 Other.
In Oct-42, 80 Fighter, 0 Flak, 20 Other.
In Nov-42, 76.92 Fighter, 0 Flak, 23.08 Other.
In Dec-42, 100 Fighter, 0 Flak, 0 Other.
In Jan-43, 100 Fighter, 0 Flak, 0 Other.
In Feb-43, 91.3 Fighter, 0 Flak, 8.7 Other.
In Mar-43, 85.71 Fighter, 0 Flak, 14.29 Other.
In Apr-43, 96.55 Fighter, 3.45 Flak, 0 Other. Fighter to flak loss Ratio, 28 to 1, Flak to fighter ratio, 0.04 to 1.
In May-43, 69.57 Fighter, 18.84 Flak, 11.59 Other. Fighter to flak loss Ratio, 3.69 to 1, Flak to fighter ratio, 0.27 to 1.
In Jun-43, 86.67 Fighter, 13.33 Flak, 0 Other. Fighter to flak loss Ratio, 6.5 to 1, Flak to fighter ratio, 0.15 to 1.
In Jul-43, 66.95 Fighter, 24.58 Flak, 8.47 Other. Fighter to flak loss Ratio, 2.72 to 1, Flak to fighter ratio, 0.37 to 1.
In Aug-43, 74.36 Fighter, 17.09 Flak, 8.55 Other. Fighter to flak loss Ratio, 4.35 to 1, Flak to fighter ratio, 0.23 to 1.
In Sep-43, 46.94 Fighter, 25.51 Flak, 27.55 Other. Fighter to flak loss Ratio, 1.84 to 1, Flak to fighter ratio, 0.54 to 1.
In Oct-43, 74.73 Fighter, 20.43 Flak, 4.84 Other. Fighter to flak loss Ratio, 3.66 to 1, Flak to fighter ratio, 0.27 to 1.
In Nov-43, 55.79 Fighter, 26.32 Flak, 17.89 Other. Fighter to flak loss Ratio, 2.12 to 1, Flak to fighter ratio, 0.47 to 1.
In Dec-43, 49.42 Fighter, 37.79 Flak, 12.79 Other. Fighter to flak loss Ratio, 1.31 to 1, Flak to fighter ratio, 0.76 to 1.
In Jan-44, 68.47 Fighter, 13.3 Flak, 18.23 Other. Fighter to flak loss Ratio, 5.15 to 1, Flak to fighter ratio, 0.19 to 1.
In Feb-44, 62.73 Fighter, 29.89 Flak, 7.38 Other. Fighter to flak loss Ratio, 2.1 to 1, Flak to fighter ratio, 0.48 to 1.
In Mar-44, 51.59 Fighter, 32.46 Flak, 15.94 Other. Fighter to flak loss Ratio, 1.59 to 1, Flak to fighter ratio, 0.63 to 1.
In Apr-44, 74.76 Fighter, 25 Flak, 0.24 Other. Fighter to flak loss Ratio, 2.99 to 1, Flak to fighter ratio, 0.33 to 1.
In May-44, 56.12 Fighter, 32.45 Flak, 11.44 Other. Fighter to flak loss Ratio, 1.73 to 1, Flak to fighter ratio, 0.58 to 1.
In Jun-44, 35 Fighter, 50.63 Flak, 14.38 Other. Fighter to flak loss Ratio, 0.69 to 1, Flak to fighter ratio, 1.45 to 1.
In Jul-44, 22.73 Fighter, 57.1 Flak, 20.17 Other. Fighter to flak loss Ratio, 0.4 to 1, Flak to fighter ratio, 2.51 to 1.
In Aug-44, 18.43 Fighter, 71.9 Flak, 9.67 Other. Fighter to flak loss Ratio, 0.26 to 1, Flak to fighter ratio, 3.9 to 1.
In Sep-44, 36.63 Fighter, 55.35 Flak, 8.02 Other. Fighter to flak loss Ratio, 0.66 to 1, Flak to fighter ratio, 1.51 to 1.
In Oct-44, 20.34 Fighter, 63.28 Flak, 16.38 Other. Fighter to flak loss Ratio, 0.32 to 1, Flak to fighter ratio, 3.11 to 1.
In Nov-44, 23.92 Fighter, 69.86 Flak, 6.22 Other. Fighter to flak loss Ratio, 0.34 to 1, Flak to fighter ratio, 2.92 to 1.
In Dec-44, 23.53 Fighter, 62.18 Flak, 14.29 Other. Fighter to flak loss Ratio, 0.38 to 1, Flak to fighter ratio, 2.64 to 1.
In Jan-45, 15.61 Fighter, 70.7 Flak, 13.69 Other. Fighter to flak loss Ratio, 0.22 to 1, Flak to fighter ratio, 4.53 to 1.
In Feb-45, 7.14 Fighter, 80.1 Flak, 12.76 Other. Fighter to flak loss Ratio, 0.09 to 1, Flak to fighter ratio, 11.21 to 1.
In Mar-45, 23.68 Fighter, 61.65 Flak, 14.66 Other. Fighter to flak loss Ratio, 0.38 to 1, Flak to fighter ratio, 2.6 to 1.
In Apr-45, 37.89 Fighter, 40.53 Flak, 21.58 Other. Fighter to flak loss Ratio, 0.94 to 1, Flak to fighter ratio, 1.07 to 1.
In May-45, 14.29 Fighter, 57.14 Flak, 28.57 Other. Fighter to flak loss Ratio, 0.25 to 1, Flak to fighter ratio, 4 to 1.
In 1942, 88.1 Fighter, 0 Flak, 11.9 Other.
In 1943, 67.57 Fighter, 22.01 Flak, 10.42 Other. Fighter to flak loss Ratio, 3.07 to 1, Flak to fighter ratio, 0.33 to 1.
In 1944, 43.35 Fighter, 45.38 Flak, 11.27 Other. Fighter to flak loss Ratio, 0.96 to 1, Flak to fighter ratio, 1.05 to 1.
In 1945, 20.45 Fighter, 64.13 Flak, 15.42 Other. Fighter to flak loss Ratio, 0.32 to 1, Flak to fighter ratio, 3.14 to 1.
Total, 44.2 Fighter, 43.96 Flak, 11.84 Other. Fighter to flak loss Ratio, 1.01 to 1, Flak to fighter ratio, 0.99 to 1.
Percentages.