Nonprofit budgeted costs for accounting services

Alright pros, let's put our advisor hats on just for our own services. What do you think an nonprofit should budget for accounting services. I am looking at this based on revenue. For example, let's say an NPO makes 2MM a year. I would say budget around 5% for either an employee or outsource accounting firm to assist with accounting and audit help. This would be around 100k. What are your thoughts, rule of thumbs, formula's, etc. ? I will check out database and guidestar. Thank you.

I have always believed 5-8% is a good rule-of-thumb, whether for-profit or non-profit, but generally higher for non-profits due to added accounting needs (meaning fund accounting, tracking support vs. program, etc.). Obviously you reach a point where it levels off and potentially declines relative to revenue. I find 8% to be a better fit for the needs of a small nonprofit, whereas a similar sized for-profit would be 5-6%. That is not sufficient to also cover an audit, though.