--- sa-stats-1.0.txt	2014-05-09 07:43:35.000000000 +0200
+++ sa-stats-1.0.txt	2014-05-24 08:00:28.000000000 +0200
@@ -269,7 +269,7 @@ sub summarize {
     #my $perc1=sprintf("%.2f",($SPAM_RULES{$key}/$NUM_EMAIL)*100);
     my $perc1=sprintf("%.2f",(($SPAM_RULES{$key}+$HAM_RULES{$key})/$NUM_EMAIL)*100);
     my $perc2=sprintf("%.2f",($SPAM_RULES{$key}/$NUM_SPAM)*100);
-    my $perc3=sprintf("%.2f",($HAM_RULES{$key}/$NUM_HAM)*100);
+    my $perc3=sprintf("%.2f",($NUM_HAM > 0 ? $HAM_RULES{$key}/$NUM_HAM : 0)*100);
     printf("%4d\t%-24s\t%5s\t%6.2f\t%6.2f\t%6.2f\n",$count+1,$key,$SPAM_RULES{$key},$perc1,$perc2,$perc3);
     $count++;
     if ($count >= $TOPRULES && $TOPRULES > 0) {
@@ -289,7 +289,7 @@ sub summarize {
   foreach my $key (sort { $HAM_RULES{$b} <=> $HAM_RULES{$a} } keys %HAM_RULES) {
     #my $perc1=sprintf("%.2f",($HAM_RULES{$key}/$NUM_EMAIL)*100);
     my $perc1=sprintf("%.2f",(($SPAM_RULES{$key}+$HAM_RULES{$key})/$NUM_EMAIL)*100);
-    my $perc2=sprintf("%.2f",($SPAM_RULES{$key}/$NUM_SPAM)*100);
+    my $perc2=sprintf("%.2f",($NUM_SPAM > 0 ? $SPAM_RULES{$key}/$NUM_SPAM : 0)*100);
     my $perc3=sprintf("%.2f",($HAM_RULES{$key}/$NUM_HAM)*100);
     printf("%4d\t%-24s\t%5s\t%6.2f\t%6.2f\t%6.2f\n",$count+1,$key,$HAM_RULES{$key},$perc1,$perc2,$perc3);
     $count++;