Next to none

While there were a few examples of suppressed weapons such as the OSS favored High Standard HDM or the SOE Welrod and hand full of others (a Stern variant), there really wasn't any wide spread use. No large scale military production or usage other than limited commando and intelligence operatives. The two ways a suppressor works is either integral suppressor (such as on the MP5SD) or threaded barrel (like on some variants of the M4) which were no were to the found on standard issue weapons. The militaries of the time decide that the bulky nature and limited noise suppression wasn't worth it. While the suppressor diminish the sound caused by hot gas exiting the barrel other sound still play a factor. Mechanical parts of the weapons moving, super sonic crack of high velocity bullets, the small explosion that propel the round, etc. Suppressor work best with smaller round and subsonic ammo, and even better with weapons with less moving parts like having a slide lock (hence the use of the mk22 hush puppy during Vietnam by US Navy SEALs). They reduce not eliminate noise so that it gives a few advantages: its hard to detect firing location, great chance of ambient noise masking, hearing distance reduced, and hearing protection for the firer.