Information is Beautiful made this visualization of the most common PINs:

According to the analysis, just 20 4-digit numbers account for 27% of all PINs:

1234	0000	7777	2000	2222	9999	5555	1122	8888	2001
1111	1212	1004	4444	6969	3333	6666	1313	4321	1010

Its frightening to know that a little over ¼ PIN codes can be cracked with just these 20 PINs! If you are one of the ones using on of these numbers - it is highly recommended that you pick another PIN.

Unguessable PINs would seem to be unrepeated pairs of numbers greater than 50 — so 8957, 7064, 9653, etc. Choose wisely.