So, one of the problems with the 12th-13th century in general is the infuriating lack of the sort of data all us moderns are used to. For the most part, written sources from this era are legal documents, like charters, or they're religious in nature, or they're narrative accounts of wars, battles, and the lives of saints, kings, and great men.

With that said, there are some textual hints that non-aristocratic "Franks" settled in Outremer. Usama ibn Munqidh, a fantastic Muslim author of the 12th century, recorded an incident involving two Franks. One had apparently been accused of some wrongdoing, and consequently had to face the village blacksmith in a trial by combat with club and shield. Certainly, neither of these men were of the military aristocracy. Beyond that, the mere fact that the crusader states could put European-style infantry into the field strongly suggests that some men of less than knightly status had come east. The question, of course, is how many.

From a military perspective, there were never anywhere near enough, which I think is probably the closest we'll get to an exact answer. Some, but not enough to significantly alter the demographics of the region. Certainly not on a scale resembling the conquest of the Americas.