I was surprised today as well. I called Apple Support for iTunes, and was told that Florida and Kentucky have forced them to charge the Telecommunications Service Tax (actually it is called the Communications Service Tax), and that for Florida it is 13%.
My monthly billed total had been up to now: $14.99, today's charge was: $16.70
Doing a reverse tax that means I was charged $1.71 (10.24%). At least I'm not being charged the full 13%.
I called the Florida Department of Revenue, read the online documents, and they state the change effective January 1, 2019. Apple waited, at least.
I verified at the revenue website: https://floridarevenue.com/taxes/taxesfees/Pages/cst.aspx that the combined rates equals 7.44% as shown below.
To that, you need to add your local county's CST rates (yes, the local county tax for CST also must be added). You can find your local county's CST here: https://pointmatch.floridarevenue.com/General/CommunicationsServicesTaxRates.aspx
It seems my local CST should be higher, but was only charged 2.8% instead.
I hope this explanation and links, as well as those posted by others here explains what has happened.
In God's Harmony