diff --git a/plot_transmission_timeline.py b/plot_transmission_timeline.py
index c849999..f2d018f 100755
--- a/plot_transmission_timeline.py
+++ b/plot_transmission_timeline.py
@@ -193,7 +193,7 @@ if __name__ == "__main__":
     print("Calculate and polt CDF...")
     # Get the frequency, PDF and CDF for each value in the series
     # copy column
-    transmission_df["gp_frequency"] = transmission_df["goodput"]
+    transmission_df["gp_frequency"] = transmission_df.loc[:, "goodput"]
 
     # Frequency
     transmission_df = transmission_df.groupby("gp_frequency")["gp_frequency"].agg("count").pipe(pd.DataFrame)