diff --git a/src/NodaUncertaintyHelper.php b/src/NodaUncertaintyHelper.php
index 5c28d8d..298feaf 100644
--- a/src/NodaUncertaintyHelper.php
+++ b/src/NodaUncertaintyHelper.php
@@ -51,6 +51,8 @@ final class NodaUncertaintyHelper {
         "O.J.",
         "Ohne Datum",
         "ohne Datum",
+        "Ohne Jahr",
+        "ohne Jahr",
         "Unbekannt",
         "unbekannt",
         "ismeretlen",