Possibly it cud be biggest but its just one tribe pashton have 60 tribes and 400+ sub clans so imagin how many people belong to pushtoon tribe and most of them dont write khan with their names we have family friends who dont write khan and they are yousafzai same goes to General Hameed Gul who was yousafzai but dont write khan with their name.
but they are all over almost now a days specially punjab and many parts of india even in bihar to bangladesh and i even know a friend from kerala who also are khan to deep is south
"The tribes most commonly to be found in the Punjab region are the
Niazai, Kundi, Miana, Bangash, Yusufzai, Hassan Zai, Mandanr, Lodhi, Kakar, Sherwani, Orakzai, Tareen, Sulemankhel sulemani, Kakazai, Karlanri, barakzai, Khizerzai, Babar and the Zamand Pathans. Of these the most widely distributed are the Yusufzai, of whom a body of 12,000 accompanied the Mughal Emperor Babur in the final invasion of India, and settled in the plains of India and the Punjab. But as a rule, the Pathans who have settled away from the frontier have lost all memory of their tribal divisions, and indeed almost all their national characteristics."
