diff --git a/nomad/metainfo/search_extension.py b/nomad/metainfo/search_extension.py
index ca49016c6bd39f9ee2f85dad841c466ab6110139..c6d4ba4003a895ca70fdd3a5426045b9010fa17e 100644
--- a/nomad/metainfo/search_extension.py
+++ b/nomad/metainfo/search_extension.py
@@ -190,5 +190,6 @@ class Search(Elastic):
     def statistic_values(self, values):
         self._statistic_values = values
         if self._statistic_values is not None:
-            self.statistic_size = len(self._statistic_values)
+            if self.statistic_fixed_size is None:
+                self.statistic_size = len(self._statistic_values)
             self.statistic_fixed_size = len(self._statistic_values)