There is no public (nor privately compiled) tracking of how many sMerits a Merit Source gets per month. A few have disclosed it at some time or other, but that’s it, and it can range from as low as a dozen to several hundreds some in the upper hundreds range). The aggregate is currently:
There is no real need to know how many a sMerit Source has nor spends (aside from inner forum control), and it would only lead to groupies posting all around where Merit Sources posts (more than now). There is a thread here that managed to find out who many of them are. If you're very keen on it, you can try to locate it (clue: it's on Meta, and last edited no further than a quarter of a fortnight ago).