Book Report have now added historical data to their reports. I can now see how many e-books I've sold since 2010, the page reads, borrows, $ earned and % for each Amazon site. 70.4% of my earnings have come from the UK store.
The best thing is their ka-ching sound when you earn some money

It's free for authors earning less than a certain amount per month (which is me

)
So how exactly do the subscription plans work?
Once your free trial is up,
assuming you're earning more than $1000/month you'll be presented with a form asking for your credit card details. All payments are processed by Stripe so you do not need to worry about security.
If you earn less than $1000/month it remains free.
If you want to learn more you can visit the website.
https://www.getbookreport.com/