diff --git a/anuga/abstract_2d_finite_volumes/neighbour_mesh.py b/anuga/abstract_2d_finite_volumes/neighbour_mesh.py
index fb7f74b25..57535e047 100644
--- a/anuga/abstract_2d_finite_volumes/neighbour_mesh.py
+++ b/anuga/abstract_2d_finite_volumes/neighbour_mesh.py
@@ -1029,7 +1029,7 @@ def statistics(self, nbins=10):
 
         N = len(areas)
         if N > 10:
-            str += '    Percentiles (%g percent):\n' % 100//nbins
+            str += '    Percentiles (%g percent):\n' % (100//nbins)
             areas = areas.tolist()
             areas.sort()