how to sort the data with defined min and max value

I am looking for generating the number of entries which fills into defined min and max values from the given data.

To put it more simple, If the data set is

Roll No: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20

The corresponding Marks are: 47, 23, 47, 45, 26, 41, 35, 39, 41, 32, 32, 29, 27, 28, 26, 41, 23, 24, 20, 26

Then the expected out put should be

Range: number

20-24: 4

25-29: 7

30-34: 1

35-39: 2

40-44: 3

45-50: 3

If required, I should be in a position to change the range (for example, 20-24 changed as 21-25), accordingly it has to calculate number of entries.

Regards

Anil