summing bar chart instead of average

app.py

@@ -90,7 +90,7 @@ bar_chart = (
     .mark_bar()
     .encode(
         y=alt.Y("Agency:N", sort="-x"),
-        x=alt.X("mean(YTD Gross):Q", title="Average YTD Gross"),  # <-- take the mean
+        x=alt.X("sum(YTD Gross):Q", title="Total Personale Expense"),  # <-- take the mean
         tooltip=[
             "Agency:N",
             alt.Tooltip("mean(YTD Gross):Q", title="Avg YTD Gross", format="$,.0f")