Question to the Department for Education:

To ask the Secretary of State for Education, what the average amount held in reserve by schools was in each year from 2010.

The average revenue balance in each local authority maintained school is published annually. The most recent figures are in the file attached and can be found in table 5 of the statistical release available at:
https://www.gov.uk/government/statistics/la-and-school-expenditure-2015-to-2016-financial-year.