There are several places you can export this data from.
Logs
Click on the Logs icon in the top right to access these reports.
Stock Log
An export of all the stock movements in a selected period.
Stock Valuations
Downloadable spreadsheets with the valuation per day of stock/inventory. This is ideal for checking past stock valuations.
Stock/Inventory Overview Screen
Go To -> Stock -> Overiew
Click on the Export button and select from these options:
Changes Summary
This summarizes the changes by item and location:
Log
This lists all the individual changes:
Quantities by Location
Quantities of items by location with their values
Quantities & Values
The quantities across all the locations with values:
Values
A reduced version of the Quantities and Values report: