You can produce an attendance report excluding nursery students.
Go to; Reporting> Reports> Attendance (red tab)> Custom Attendance Report.
Refer to:
In this report you can select the Years you want to report on under the header "Include Years"- you can therefore select all years apart from nursery. (Click and drag your mouse to select multiple year groups.)
Click "Choose." This will show overall attendance percentages for each year group.