Table:
text: Convoys ONS 20/ON 206
Tables
Tables
Date_ Number_ Type_ Captain Casualties
16 Oct 1943 U-470 VIIC O/L Grave 46
16 Oct U-964 VIIC O/L Hummerjohann 47
16 Oct U-844 IXC O/L Moller 53
17 Oct U-540 IXC K/L Kasch 55
17 Oct U-631 VIIC O/L Kruger 53
17 Oct U-841 IXC K/L Bender 26

Question: What is the average number of casualties for the convoy with a number of U-844 among the ONS 20/ON 206 convoys?