There was a nice chart, which compared the voting by age to "time you have to leave with this decision". Old people who just don't give a fuck about future voted for leave, young people who have to deal with the results for decades voted for remain.
About first question: I doubt anybody in this forum could have experience first hand. EU was founded 1993, but originated from other union agreements much earlier (see:
https://en.wikipedia.org/wiki/European_Union#Structural_evolution)
About second question: Don't know for sure, but I know people working in financial related jobs or trade and export would've voted for remain. Same for immigrants. Maybe people with these criteria live there.
I like to add:
Disregarding if this decision was right or wrong, what David Cameron did was just pure careless. At first, he started the talks about referendum to calm his OWN political party because he doesn't achieve enough, and then tries to hold them back when they are actually going for it. And guess what: Now that shit is boiling, this guy decides to leave his position in October, right in time so some other poor soul has to deal with the negotiations with the EU about the leave.
This man is just a coward to me. A blatant opportunist more interested in his own success then the future of his country and fellow countrymen.
Edit: Found said infographic:
https://scontent.ftxl1-1.fna.fbcdn.net/v/t1.0-9/fr/cp0/e15/q65/13507177_1025349370880775_4082477719157881339_n.jpg?efg=eyJpIjoidCJ9&oh=ec7fa515eb31c5f4ea225e2586e83cd7&oe=57C3CADB