The Revenue by Client report will display the revenue by client within specific months. You have the option to filter by year and client, in addition to filtering by 'Total Collected' and 'Total Billed'.  Total collected will be any payment received, whereas Total Billed will include invoices sent. After making any modifications to your filters, you will need to select the 'Update' button in the upper right corner for those changes to be reflected in your report.