As Astir says it depends on age. My driving instructor reckoned the number of hours required to pass your test, was about the same as your age.
As Coldair remarked, its more a reflection on how good your instructor is. I was bashing around the circuit seemingly unable to land the aircraft. Then I had a different instructor, one hours instruction, problem solved.
For willy waving purposes, I will not get mine out, 22 hours (aged 41).