diff --git a/core/src/com/galvarez/ttw/model/InfluenceSystem.java b/core/src/com/galvarez/ttw/model/InfluenceSystem.java
index 4a9f05b..406ea98 100644
--- a/core/src/com/galvarez/ttw/model/InfluenceSystem.java
+++ b/core/src/com/galvarez/ttw/model/InfluenceSystem.java
@@ -361,35 +361,20 @@ private void updateInfluencedTiles(Entity e) {
   private void accumulatePower(Entity empire) {
     InfluenceSource source = sources.get(empire);
 
-    int increase = source.growth + source.influencedTiles.size();
+    int increase = source.growth * source.power / 100;
     if (increase > 0) {
       Diplomacy diplomacy = relations.get(empire);
       List<Entity> tributes = diplomacy.getEmpires(State.TRIBUTE);
       int remains = increase;
       for (Entity other : tributes) {
         int tribute = min(remains, increase / tributes.size());
-        sources.get(other).powerAdvancement += tribute;
+        sources.get(other).power += tribute;
         remains -= tribute;
       }
       increase = remains;
     }
 
-    source.powerAdvancement += increase;
-    if (source.powerAdvancement < 0) {
-      source.power--;
-      source.powerAdvancement = getRequiredPowerAdvancement(source) + source.powerAdvancement;
-    } else {
-      int required = getRequiredPowerAdvancement(source);
-      if (source.powerAdvancement >= required) {
-        source.powerAdvancement -= required;
-        source.power++;
-      }
-    }
-  }
-
-  public int getRequiredPowerAdvancement(InfluenceSource source) {
-    // TODO the base power should depend on the empire
-    return source.power + 1;
+    source.power += increase;
   }
 
 }
diff --git a/core/src/com/galvarez/ttw/model/components/InfluenceSource.java b/core/src/com/galvarez/ttw/model/components/InfluenceSource.java
index 7097d3c..1d6dcd7 100644
--- a/core/src/com/galvarez/ttw/model/components/InfluenceSource.java
+++ b/core/src/com/galvarez/ttw/model/components/InfluenceSource.java
@@ -19,10 +19,9 @@ public final class InfluenceSource extends Component {
 
   public final Set<MapPosition> influencedTiles = new HashSet<>();
 
+  /** In percents. */
   public int growth;
 
-  public int powerAdvancement = 0;
-
   public final List<Entity> secondarySources = new ArrayList<>();
 
   public final Modifiers modifiers = new Modifiers();
diff --git a/core/src/com/galvarez/ttw/screens/overworld/MenuBuilder.java b/core/src/com/galvarez/ttw/screens/overworld/MenuBuilder.java
index 31f17a9..182ae07 100644
--- a/core/src/com/galvarez/ttw/screens/overworld/MenuBuilder.java
+++ b/core/src/com/galvarez/ttw/screens/overworld/MenuBuilder.java
@@ -185,11 +185,8 @@ public void buildSelectionMenu(final MapPosition tile, Entity e) {
     if (e != null) {
       addDescription(e);
       InfluenceSource infSource = e.getComponent(InfluenceSource.class);
-      if (infSource != null) {
-        int percent = 100 * infSource.powerAdvancement
-            / world.getSystem(InfluenceSystem.class).getRequiredPowerAdvancement(infSource);
-        selectionMenu.addLabel("Power: " + infSource.power + " (+" + percent + "%)");
-      }
+      if (infSource != null)
+        selectionMenu.addLabel("Power: " + infSource.power + " (+" + infSource.growth + "%/turn)");
     }
 
     Entity source = influence.getMainInfluenceSource(world);