Complex sentence: The NS-45 was built in small numbers at factory number 74 in the last two years of the war; 75 exemplars were made in 1944 and 120 in 1945.
Split into simpler sentences: The NS-45 was built in small numbers at factory number 74 between 1944 and 1945. More precisely, 75 exemplars were made in 1944 and 120 in 1945.