If you wish to have a more sophisticated analysis, you can add a profile to the estimates on each code by using the Flexed Budget function.
Select whether you wish to spread the budget monthly, quarterly or manually. By selecting to 'Spread Manually', you will be able to enter specific amounts against individual months.
There are two reports that look at the flexed budget: Monthly Flexed Budget and Quarterly Flexed Budget, allowing you to compare actual spent/receipt at the given point in the year (calendar month or quarterly) with the Year-to-Date budget.
The ordinary Summary Reports will not be changed and will still provide reports on the total for the year to date spend against the annual budget.