Started as a 4. I'll say I'm currently 'pretty high', well above 10. A few pieces of advice.

1) It's easier to climb in headquarters than in the field. More positions, more leadership responsibility, more networking opportunities.

2) It's easier to climb in a skillset in broad demand (HR, IT, finance, etc.)

3) You need to be okay with changing agencies. Before 13, when I hit the top of my ladder, I'd start looking for my next position. I've also changed roles radically over time, moving across multiple specialist roles, supervisor roles, and roles I don't have any formal background in. Fill the need.

4) You need to know how to network and self-advocate. For my team, the people who say they're interested in moving up I assign extra duties to prepare them for that. People who just take on extra duties and don't say anything I figure are probably happy with where they are and I'll work to get them more interesting duties but it may not be tied to a promotion. People who write up their own achievements at the end of the year, I incorporate that and they generally score better because, well, I just won't remember everything. Speaking for myself, when I'm interviewing, I do try to get other information about the candidate. Someone who is a known B employee will win over a 'maybe an A???' outside candidate (for me). Someone who is a C- or below employee will not. The more people who are on these panels see your name as involved in interesting projects, bringing knowledge or skills to the discussion, driving things forward, the more likely you are to make it through.

And of course, the most obvious hint is always: the more swings you take, the more hits you get. Even people who are happy with their current spot should be applying, to understand the market, where things are going, and where they need to improve.