How difficult is it to get into the “department”?

At 25, pass the civil service exam and make it
At 26, become a second-level clerk
At 27, become a first-level clerk
At 29, become a fourth-level director clerk
At 30, become a deputy section-level official(Deputy mayor, most people stop here)
At 33, become a third-level director clerk
At 35, become a second-level director clerk
At 37, reach the rank of full section-level chief
At 39, become a first-level director clerk
At 40, become a fourth-level research officer
At 42, become a deputy division head (the very few at the top of the county-level “pyramid”)
At 43, become a third-level research officer
At 46, become a second-level research officer
At 48, reach the rank of full division head(County magistrate, only 4.4% of people reach this level)
At 50, become a first-level research officer
At 53, become a second-level inspector
At 55, become a deputy bureau-level official
At 58, become a first-level inspector
At 60, reach the rank of full bureau-level(City mayor, in charge of an entire region)
At 63, become a deputy minister-level official
At 67, reach the rank of full minister-level (promotion ratio 35000:1—how big must this official be)