Electric current in mic
All mics work by converting energy in a tiny vibrating diaphragm to electricity. There are two common ways that this is done. In a dynamic mic the most common type works like a loudspeaker in reverse (in fact you can use a LS as a poor quality mic, it works). Here the mic inpedance itself is typically around 200R, and it is designed to work into an impedance of about 2k. The actual sensitivity varies a lot, but under "normal" conditions we might see a voltage of around 5mV across the mic. This means that it is generating a current in the order of 2.5uA.

The other common type of mic is a capacitor (condenser) mic. There are various types but in these the diaphragm (which is part of a charged capacitor) is connected to a FET preamp in the mic itself. Not sure what the current would be for these (I expect it varies quite a lot with diaphragm size and so on) but anyway you never see that current at the XLR connector on the mic body. What you see there is the preamp output, which is designed to be of similar magnitude to a dynamic mic, so that it can use the same preamp (which is now perhaps better described as a secondary preamp).

The mic in your question is a condenser mic by the way. It quotes 33mV/Pa. According to this chart, 2Pa is the sound of a jackhammer (they don't say from how close, but loud!) - so 1Pa is still going loud - louder than most singers, except maybe that guy in ACDC. So I would think that our 5mV figure is in the right ballpark here, or perhaps slightly on the low side. (As there is really no "standard vocalist" you are not going to get a precise answer anyway.)