Hi,
Exports are for details, not for totals.
If you want something that calculates totals for you, then you don't want to use exports.
If you configure a report like this (
monosnap.com/file/N4Tsd4b3LN69MdGVSOlfzKHiR0qVEb
), it will give you a graph with one point per month with the total tax amount for each month.
There is however no option to break that per tax rate.
Also, in your messages, you avoid talking about my first answer to you regarding this topic:
Go in the menu System>Taxes and then click on the "manage tax rates" button.
There you'll have a listing of your tax rates. And you'll have a column for the total amount of taxes for each rate, and a column for the total amount of the orders for each rate. And you'll have filters on the top right of the listing to set a date range and select the order statuses to take into account.
This area was especially made for merchants to be able to easily get the total tax amounts per rate for the periods they want for tax reports. The interface is simplicity itself there. You select the starting date, the ending date, and the statuses to take into account and you can just read the amounts for each rate for the period selected.
Reading your last message, it looks to me that this interface is the most fitting to your needs.