If you are using a list, try using a pivot table.
When this is done you can group any items by selecting them, right clicking on the table and selecting "group".
( If they are dtaes you can group by weeks, months, years, whatever)
If there are items you don't wish to show, right click the table, choose " fields" and select the fields you want to hide.
Making a graph is easy: slect any item of the pivot table and push the "F11" button.
You will get the default graph which you can customize as you wish.