I have data in such way:

-------Set1 Set2 SetA SetB
Day1 3591 8690 7202 6796
Day2 5766 9514 9309 9344
Day3 4939 0023 4607 7550
Day4 5472 3489 6872 2455

*Note that some data set will contain leading zero(s), which must be retained and included in calculating the frequency.

1 am trying to find out the frequency of each digit from each set1, set2, setA, setB
Example,

For Set1, FIRST digit:
Digit Frequency
0-----0
1-----0
2-----0
3-----1
4-----1
5-----2
6-----0
7-----0
8-----0
9-----0

3 Digits that has lowest frequency (sorted ascending order, below is just example how it looks):
Digit Frequency
9-----11
0-----24
7-----30

For Set1, SECOND digit:
Digit Frequency
0-----0
1-----0
2-----0
3-----0
4-----1
5-----1
6-----0
7-----1
8-----0
9-----1

3 Digits that has lowest frequency:
Digit Frequency
X-----n
X-----n
X-----n


For Set1, THIRD digit:
Digit Frequency
0-----0
1-----0
2-----0
3-----1
4-----0
5-----0
6-----1
7-----1
8-----0
9-----1

3 Digits that has lowest frequency:
Digit Frequency
X-----n
X-----n
X-----n


For Set1, FOURTH digit:
Digit Frequency
0-----0
1-----1
2-----1
3-----0
4-----0
5-----0
6-----1
7-----0
8-----0
9-----1

3 Digits that has lowest frequency:
Digit Frequency
X-----n
X-----n
X-----n


The above search to be repeated for set2, then setA, SetB...
But as long as you guys can shed me light on how to do it for set one, i can take care of the rest of the data set

Many thanks in advance.

Regards,
Tristan