This tool summarises your acount income and outgoings on a monthly basis. You can download the data using the link beneath the tables.
This tool is still in development, but should currently help you collect the records you need for tax calculations. The historic currency rates are collected from https://cryptocompare.com, for most of 2017 this is interpolated hourly data, but from 2018 the colected data in minutely to improve accuracy in volatile market conditions.
The earliest date for which figures can be produced is 1st Jan 2017, and to improve the accuracy of figures, please cancel any open orders and don't carry out any transaction for one hour before using this.