Hi @sylvie.charrette - each report has an overall trend line and can show trend within each question or driver area as you click down.  If you want to export a view of trend, you can also add a section to the Executive Summary or Overview report (by clicking the three dots in the uppermost right > add section) called Scores Trend.  If you add this section and then export the report to spreadsheet it will break down the question areas into rows and pulses into columns.  

I hope this helps!