diff --git a/src/osm/jp/postgis/CoverageAll.java b/src/osm/jp/postgis/CoverageAll.java
index f6dc1f3..cc028e6 100644
--- a/src/osm/jp/postgis/CoverageAll.java
+++ b/src/osm/jp/postgis/CoverageAll.java
@@ -141,8 +141,13 @@
                 rset2.close();
             }
 
-            cover.par = (double)cover.molecule / cover.denominator;
-            cover.par *= 100.0D;
+            if (cover.denominator > 0) {
+                cover.par = (double)cover.molecule / cover.denominator;
+                cover.par *= 100.0D;
+            }
+            else {
+                cover.par = 0.0D;
+            }
             data.add(cover);
         }
     }