No limit i guess. It can take as short as a year to as long as forever
.
My best guess is assuming if you don't change job, stay in one company,
Average Performer: 10 years to get from Executive to AM/Mgr
Above Average Performer: 10 years to get from Executive to Snr Mgr/AD
Excellent employee with huge potential 10 years can reach Director (Public Sector)
Excellent Employee with huge potential + Huge connection 10 Years can be CEO in private sector.
Just my best guess.