diff --git a/w2v-server.pl b/w2v-server.pl
index af8b55d..2cd708c 100644
--- a/w2v-server.pl
+++ b/w2v-server.pl
@@ -415,7 +415,7 @@
   g.append("a")
 	 .attr("xlink:href", function(word) {return "/?word="+word;})
 	 .attr("title", function(d, i) {
-		 return "rank: "+i +"  "+"freq. rank: "+data.ranks[i];
+		 return "rank: "+i +"  "+"freq. rank: "+data.ranks[i].toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
 	 })
 		.append("text")
    .attr("text-anchor", "top")