I am not sure about merit of each Zone but let me tell u my findings,
Total
113 Candidates appeared at Swat center and marks are
66 65 63 61 61 61........................
Total
171 Candidates appeared at Mardan Center and marks are
70 69 68 68 64..........................
one of my Friend checked result of 800 candidates from peshawar center and marks are
74 70 70 68 68 68 68......................
I dont know about Abbotabad Center but my friend told me that top marks are
71 70 68 68 66 65.......
I hope this will give u all a clear Idea and make U understand the scenario.
Best Regards!