Query to SUM DAILY TAT

i am working with a query to get a daily TAT report i have an Access Database an a table named "Procesado" where i have a date field named "ProcessDate" and other field named TAT what i need is to obtain in a daily basis the percentage of TAT of all items that can be various the same date. to obtain the tat i need to divide TAT less than 1 day into TAT greater than 1 day grouped by date the ouput would look like the following: Table Procesado ProcessDate TAT 06/10/2016 1 06/10/2016 5 06/10/2016 1 06/11/2016 1 06/11/2016 4 Example desired Ouput: 06/10/2016 98% 06/11/2016 96% 06/15/2016 98% 06/16/2016 99%