@Feomater that can really vary quite a bit based on the individual - especially how much you want to just do the dungeon mob grind vs boss fights (bosses are about the loot, but never good exp/hour). I found a lot of my own time taking my 1st group from 1-60 was spent learning how to control everyone, what sort of spells & "rotation" was needed, etc. If I followed the exact same path again I'd expect I could do it in 1/2 - 1/4 the time it took on round 1 (even with the recent Gor'Shek nerf).

I don't recall how fast I did 1-12, but it was quick - 1 afternoon session. Once I got into RFC and figured out what I was doing (took a run or two to learn the pulls and re-keymap just about everything) I was in the 20k/hour area. I left early to to WC, but that was a loss of exp/hour. In BRD and SFK I was just a bit below 30k/hour when I wasn't making mistakes. Once I got to SM, my exp/hour just about exactly matched my level - i.e. 30k/hour when I started at L30 and got up to just over 40k/hour when I left at L41. ZF was a nice bump up to nearly 50k/hour - even when I was just doing zombies and scarabs when I started at L43. ST can be 60k/hour if you just do the mob grind at level 50-52. BRD is an easy 60-80k/hour doing the prison and ring of law farms. LBRS at L58+ had me over 80k/hour doing the orc & troll sections - slower in the ogre area and once I got the spider parts.