Measured: EXP per kill, from the game files. Estimated: the EXP needed per level, so the kills and time too. Time and EXP per hour are arithmetic on the kill speed you typed. They count solo kills only, with no party bonus, deaths or travel, and we have no live EXP per hour figures to check them against.
60: 1,209,994
61: 1,276,301
62: 1,346,242
63: 1,420,016
64: 1,497,832
65: 1,579,913
66: 1,666,492
67: 1,757,815
68: 1,854,143
69: 1,955,750
70: 2,062,925
Level → EXP to the next level. Nexon has not published the Classic World table; this is the older game's table, not confirmed for Classic World. Report a mismatch and the table gets fixed.