Pulling data out of lists / a database

I have a long lists of various accounts. Each account has many entries. I am trying to find a way to sum up all of the entries for each account without having to manually input the formula.

I am then trying to pull out the totals for each account to do some analytics.

I've put together a brief example of what I'm trying to do below (except that I'm dealing with several hundred accounts):

Sorry for the poor formating, this is my first attempt at posting. It should be easier to follow in the attached file.

Starting Data

Customer Purchases ($)
1 15
1 25
1 8
1 65
1 12
1 20
1 33
2 8
2 15
2 8
3 10
3 15
3 20
3 25
3 10
3 10
4 2
4 20
4 25
5 15
Total 361

Step 1

Customer Purchases ($)
1 15
1 25
1 8
1 65
1 12
1 20
1 33
Subtotal 1 178

2 8
2 15
2 8
Subtotal 2 31

3 10
3 15
3 20
3 25
3 10
3 10
Subtotal 3 90

4 2
4 20
4 25
Subtotal 4 47

5 35
Subtotal 5 35

Total 381



Final Product

Customer Purchases ($) % Total
1 178 46.7%
2 31 8.1%
3 90 23.6%
4 47 12.3%
5 35 9.2%
Total 381 100.0%