Howie's Question

At dinner tonight Howie posed a very interesting question. "Why do most names that are initials have the letter J in it?"  I asked him to elaborate and he gave me a few examples. "You know...AJ,  JD, JJ...etc." I started thinking about it and he's right.  Of course there are names with initials without the letter 'J', but the majority have 'J' in it.  Here's my list. I've put an asterisk next to the initials of people we know. Let me know if I've missed any.

AJ*, BJ, CJ*, DJ*, JJ*, LJ*, MJ*, PJ, RJ, TJ*, JC, JD*, JK (Rowling), JR , JZ

UPDATE: OJ...how could I forget that one!