Hollywood loves 'em.
Authors love 'em.
47, in the genetically-induced flesh. All true hitmen are bald. In fact, it's probably for the better, as getting attached to a hitman can really suck when he turns on you and shoots you in the kneecaps. And that he does, due to the simple fact that his genetic engineering has rendered him emotionless and unquestionably obedient to his masters. Since your employers literally control you, you've got to listen to them.