In the insights section, you have a monthly accounting-like view of all your sales and costs for your marketplace
Alongside the profit analytics per ASIN, you can analzse your metrics on a monthly basis.
Here are a few details on the metrics:
Sales: All sales (organic and sponsored sales)
The metrics are up to date according to Amazon reports. The numbers might change as Amazon updates its reports on a daily basis. The further you look into the past, the more reliable the data is!
Explore a detailed breakdown of key metrics in the Profit and Loss statement (P&L) right here.