String height will depend on personal preference, string type, etc. Generally, lower tension strings like gut are set higher. I use steel strings and generally have my height at 4mm to 8mm (G to E).
The 15mm height on the E you quoted seems a little high to me. That might fly with unwound guts, but I'd hate to encounter a 15mm E on steel. I am of course presuming you are measuring to the bottom of the string and not including the string diameter by measuring to the top of the string.
Poll, schmoll. You can use statistics to prove anything. 67% of people know that.