Where to check the experience needed to level up?

If you play mobile version of the game you can find the experience bar is in the upper left corner of the game screen, with a star icon and the game level. The first number on the bar is the amount of experience you have at the moment, the second number states the amount of experience you need in order to gain the next level.

If you play Facebook version of the game you can find the necessary amount of experience points for each level in the list below:
2 - 100
3 - 110
4 - 125
5 - 140
6 - 160
7 - 180
8 - 210
9 - 250
10 - 300
11 - 350
12 - 420
13 - 510
14 - 620
15 - 770
16 - 950
17 - 1200
18 - 1500
19 - 1900
20 - 2500
21 - 3100
22 - 4000
23 - 5300
24 - 7000
25 - 9500
26 - 12500
27 - 17000
28 - 23000
29 - 32000
30 - 45000
31 - 60000
32 - 67000
33 - 74000
34 - 81000
35 - 89000
36 - 97000
37 - 108000
38 - 118000
39 - 130000
40 - 143000
41 - 158000
42 - 173000
43 - 191000
44 - 210000
45 - 230000
46 - 253000
47 - 279000
48 - 307000
49 - 337000
50 - 371000
51 - 408000
52 - 449000
53 - 493000
54 - 543000
55 - 597000
56 - 656000
57 - 722000
58 - 794000
59 - 874000
60 - 961000
61 - 1000000