diff --git a/python/obitools3/commands/stats.pyx b/python/obitools3/commands/stats.pyx
index 6e1718a..62431e1 100755
--- a/python/obitools3/commands/stats.pyx
+++ b/python/obitools3/commands/stats.pyx
@@ -251,7 +251,10 @@ def run(config):
     for i in range(len(sorted_stats)):
         c = sorted_stats[i][0]
         for v in c:
-            print(pcat % tostr(v)+"\t", end="")
+            if v is not None:
+                print(pcat % tostr(v)+"\t", end="")
+            else:
+                print(pcat % str(v)+"\t", end="")
         for m in config['stats']['minimum']:
             print((("%%%dd" % lmini[m]) % mini[m][c])+"\t", end="")
         for m in config['stats']['maximum']: