What is a normal order cancellation rate for FBA orders?

I noticed that about 7-8% of my FBA fulfilled orders are routinely cancelled probably due to a fulfillment miss by Amazon. My seller fulfilled orders are cancelled at a much lower rate. When an order is cancelled it means that my advertising dollars were wasted. I’m wondering what percentage of FBA orders get cancelled for other sellers using FBA. Please share your experience with this. Is there a way to reduce FBA orders from being cancelled?

Thanks!