surfer population

Estimating the number of surfers in a given region, citywide to worldwide, has always been a difficult task, starting with the most basic defining terms. What constitutes a surfer? Do bodysurfers count? Bodyboarders? Wave skiers? Do people who rent surfing equipment count? What separates an active surfer from an inactive surfer? Or phrased another way, how many times a year does somebody have to s...