My DS1 walked at 15 months while DS2 was 21 months before he pulled himself up and began walking.He was a fast crawler though, and could get what he wanted by pointing to it and crying until someone, usually his older brother got it for him.
I missed him taking his first steps though, as I had let both boys at my MIL's or a few hours.When I left him there he was still crawling, when I returned he was walking behind her at the front door!.When I expressed my joy and amazement she just casually said "Oh he has been walking all over the place here"
His two youngest children were , like him, late walkers.Both of them almost 2 years before taking their first steps.