46 to 47 = 2.7M XP
47 to 48 = 2.9M XP
48 to 49 = 3.1M XP
49 to 50 = 3.3M XP
50 to 51 = 5.4M XP
51 to 52 = 5.7M XP
52 to 53 = 6.1M XP
53 to 54 = 6.5M XP
54 to 55 = 6.9M XP
55 to 56 = 9.8M XP
56 to 57 = 10.5M XP
57 to 58 = 11.1M XP
58 to 59 = 11.8M XP
59 to 60 = 12.5M XP
60 to 61 = 19.8M XP
61 to 62 = 20.9M XP
62 to 63 = 22.1M XP
63 to 64 = 23.4M XP
64 to 65 = 24.6M XP
65 to 66 = 34.6M XP
66 to 67 = 36.5M XP
67 to 68 = 38.4M XP
68 to 69 = 40.4M XP
69 to 70 = 42.4M XP
70 to 71 = 44.6M XP
71 to 72 = 58.5M XP
72 to 73 = 73.6M XP
73 to 74 = 90.0M XP
74 to 75 = 100.8M XP
75 to 76 = ~170M XP
76 to 77 = 220M XP
77 to 78 = 358M XP
78 to 79 = 588M XP
79 to 80 = 2.1 Billion XP!
if you have a clan hall you get the buffs there, and you can solo anywhere it can take you. then soe and repeat. for anyone else trying to solo, it gets really bad at 73. note that you can get buffs at the beast farm until this level. also, if you do the quest in swamp of screams you can get buffs from the NPCs there. but at 73 without a pole it just doesnt work as well as it used to. (havent actually done this quest, but its on the stratics website if anyone cares to look it up).
Your hero friend is not XPing well then. At 78 you can get 0.15-18 a buff run with a descent duo, solo with outside PoF you could get about 0.28+
Now 79 is a totally different story, you will then be looking at 0.05% a buff with a descent duo, my friend soloing with outside PoF can manage 0.08
There are far better ways to XP though, a CoV party at monastery or a perfectly set up group at pagans.
I havent tried to solo at pagans yet but that sounds like a crazy enough idea to work lol.