diff --git a/pyproject.toml b/pyproject.toml
index caeec82..4aa512b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "ssb-konjunk"
-version = "0.1.15"
+version = "0.1.16"
 description = "SSB Konjunk"
 authors = ["Edvard Garmannslund <ged@ssb.no>"]
 license = "MIT"
diff --git a/src/ssb_konjunk/statbank_format.py b/src/ssb_konjunk/statbank_format.py
index 964f3e1..9860c19 100644
--- a/src/ssb_konjunk/statbank_format.py
+++ b/src/ssb_konjunk/statbank_format.py
@@ -1,5 +1,7 @@
 import pandas as pd
 
+from ssb_konjunk import prompts
+
 
 def format_time_period(
     df: pd.DataFrame,
@@ -23,7 +25,7 @@ def format_time_period(
     if quarter != "" and month == "":
         df[col_name] = f"{year}K{int(quarter)}"
     elif quarter == "" and month != "":
-        df[col_name] = f"{year}M{int(quarter)}"
+        df[col_name] = f"{year}M{prompts.validate_month(month)}"
     else:
         df[col_name] = f"{year}"