diff --git a/src/seismic_hazard_forecasting.py b/src/seismic_hazard_forecasting.py
index 7ba0d77..5b1bd86 100644
--- a/src/seismic_hazard_forecasting.py
+++ b/src/seismic_hazard_forecasting.py
@@ -652,7 +652,7 @@ verbose: {verbose}")
         lambdas = np.array(rate_forecast/bin_dur, dtype='d')
         lambdas_perc = np.array(1.0, dtype='d')
 
-        np.savetxt('activity_rate.csv', np.vstack((lambdas, lambdas_perc)).T, header=f"Activity Rate (Events per {time_unit}), percentage",
+        np.savetxt('activity_rate.csv', lambdas, header=f"Activity Rate (Events per {time_unit})",
                    delimiter=',', fmt='%1.4f')
 
     if forecast_select: