Virtually all. Some were just hand prints. But does it matter if it's 100% or 90%?

Wikipedia says this:

'The most common themes in cave paintings are large wild animals, such as bison, horses, aurochs, and deer, and tracings of human hands as well as abstract patterns, called finger flutings. The species found most often were suitable for hunting by humans, but were not necessarily the actual typical prey found in associated deposits of bones; for example the painters of Lascaux have mainly left reindeer bones, but this species does not appear at all in the cave paintings, where equine species are the most common. Drawings of humans were rare and are usually schematic rather than the more detailed and naturalistic images of animal subjects. One explanation for this may be that realistically painting the human form was "forbidden by a powerful religious taboo."'

...

'Henri Breuil interpreted the paintings as being hunting magic, meant to increase the number of animals.

'An alternative theory, developed by David Lewis-Williams and broadly based on ethnographic studies of contemporary hunter-gatherer societies, is that the paintings were made by paleolithic shamans.[15] The shaman would retreat into the darkness of the caves, enter into a trance state and then paint images of their visions, perhaps with some notion of drawing power out of the cave walls themselves.

'R. Dale Guthrie, who has studied both highly artistic and publicized paintings and a variety of lower quality art and figurines, identifies a wide range of skill and ages among the artists. He hypothesizes that the main themes in the paintings and other artifacts (powerful beasts, risky hunting scenes and the representation of women in the Venus figurines) are the fantasies of adolescent males, who constituted a large part of the human population at the time.[16][verification needed] However, in analysing hand prints and stencils in French and Spanish caves, Dean Snow of Pennsylvania State University has proposed that a proportion of them, including those around the spotted horses in Pech Merle, were of female hands.'