Is this normal wear and tear or excessive damage?

[Tammy Mason]

So this past weekend had a tenant move out that lived there 17 months. They left behind around 100 holes in the wall (nail holes), rather large holes in my opinion, that I will probably need to plaster and paint over as it looks quite bad as is. I still have their 500 dollar deposit but I want find a clear definition on of this falls under normal wear and tear or not. I wanted to get some opinions for more experienced landlords, also if you think it is excessive how much of the deposit should I keep?