APTA's most recent ridership report says 95,000 on the average weekday for all SEPTA light rail (which would include the Norristown high speed line in addition to the streetcars).
I clicked through to Nexis' wiki link. I see where it says 120,450 (supposedly not including the Norristown line), however when I click on the citation and go to the actual SEPTA source document for that, the number 120,450 does not appear anywhere in the document. It's 76 pages long and mostly text, so I admit I haven't read all of it, but running a search for that number does not produce any results.