Resume question: how to describe multiple promotions at the same company?

I’ve spent almost my entire career (I’m in my early 30s) with one employer. I’ve worked hard and have moved up the ladder here, having been promoted multiple times. If keeping my resume to one page, how do I address those multiple positions? I can narrow down five different titles at one employer to three that are the most significant (the other two “promotions” were basically just a way to have me doing similar responsibilities but with slightly more authority). But how do I address timelines for changes within those jobs? For example – one of the positions I held, I took on management responsibility about halfway through that position. When describing it, do I just say “managed 2 staff members” or do I put something like “managed 2 staff members, starting x date”?