 These measures significantly improved the performance of the remaining Italian submarines (in 1941, about half were recalled to the Mediterranean following heavy submarine losses in that theatre); the average tonnage sunk by BETASOM submarines rose from 3,844 Gross Register Tons (GRT) in 1940 to 27,335 GRT in 1942 (and, respectively, from 7,779 GRT to 68,337 GRT per actually operating submarine).The tonnage sunk for every lost submarine was 32,672 GRT in 1940 (opposed to 188,423 GRT for German submarines), 20,432 GRT in 1941 (70,871 GRT for Germans submarines), 136,674 GRT in 1942 (68,801 GRT for German submarines) and 13,498 GRT in 1943 (11,391 GRT for German submarines).Between February and March 1942, five BETASOM submarines (along with six German U-boats) took part in Operation Neuland, sinking 15 of the 45 Allied merchant ships destroyed during this operation.