Thought I'd mention this here, as we all use KDP and other online bookstores when we publish. Apart from one notable exception (looking at you, Kobo), these stores allow you to download up-to-date reports containing unit sales and royalties.
Unfortunately it can take a bit of work to get the data out of these reports and display it in a meaningful fashion.
Salescanner is a PC program which imports the sales spreadsheets you can download from various sites, merge all the figures, and display daily and monthly totals.
I use it daily, and I'm always tweaking it to do more.
At the moment it's useful for Smashwords, Kobo (those once-a-month invoices they do), KDP, Google Play and Authors' Republic (audiobooks).
It shows freebies, unit sales, paperbacks and KENP.
You can also set and update the currency exchange rate. Everything displays in USD, this just means the 'foreign' income is added correctly.
Anyway, it's free to download and use:
http://www.spacejock.com/SalesScanner.htmlAnd a truly useful pic with no data showing: