I searched for a while trying to find out how much experience your hero gets from attacking an NPC, and I couldn't find it. But, I was able to combined the following pages to calculate the XP:
http://bbs.evony.com/showthread.php?t=75734
http://www.theevonywiki.com/index.php/NPC#NPC_Troop_Count_per_Level
From actual experiments, I have found that only the NPC's losses count toward experience, not the player's losses. These numbers match up exactly (given the number of traps and abatis destroyed) as of recently.
The tables show how much experience the hero gains from each kind of unit destroyed. You can take out the abatis if you are not sending horses, and take some traps as well.
NPC Lvl 1 NPC Lvl 2 NPC Lvl 3 NPC Lvl 4 NPC Lvl 5 NPC Lvl 6 NPC Lvl 7 NPC Lvl 8 NPC Lvl 9 NPC Lvl 10
Warrior 152.5 152.5 610 1220 2287.5 12200 36600 45750 183000 1220000
Scout 0 0 0 0 0 0 0 0 0 0
Pikeman 360 405 1440 3600 9000 6750 27000 60750 162000 0
Swordsman 405 540 877.5 1350 4725 7425 10125 54000 27000 0
Archer 135 405 540 1350 3375 6750 10800 40500 91125 0
Cavalry 228 712.5 1710 4275 5700 12825 21375 57000 71250 0
Cataphract 0 0 0 0 0 0 0 0 0 0
Transporter 0 0 0 0 0 0 0 0 0 0
Ballista 0 0 0 0 0 0 0 0 0 0
Battering 0 0 0 0 0 0 0 0 0 0
Catapult 0 0 0 0 0 0 0 0 0 0
Trap 8750 16187.5 17500 39375 32812.5 37187.5 49000 63000 78750 96250
Abatis 0 9212.5 16750 31406.25 31406.25 25125 46900 60300 75375 92125
Archer's Towers 0 0 35425 29975 68125 81750 100825 130800 163500 199797
Rollinglog 0 0 0 0 47250 59850 69300 90720 113400 138600
Defensive Trebuchet 0 0 0 0 0 66400 116200 149400 190900 228250
10030.5 27615 74852.5 112551.25 204681.25 316262.5 488125 752220 1156300 1975022
Sorry it looks so ugly. If someone wants to, you can repost it pretty.
