Get your historical Northpass data into Salesforce to export data as you see fit.
Click the Apps tab and select Integrations.
Click Configure for the Salesforce V2 app
Click the Send to Email button, which will trigger an email to be sent to the email address associated with the account that requests the data. Within the email, you will receive a zip file that contains a CSV of the data & you will want to use that CSV when importing your data into Salesforce.