diff --git a/adm/datintro.nw b/adm/datintro.nw
index 3e828fa..891156b 100644
--- a/adm/datintro.nw
+++ b/adm/datintro.nw
@@ -16,7 +16,7 @@ IMGNAME=datintro23
 We don't change the automation every year.
 It's a space-separated list.
 <<constants>>=
-YEARS=23 24
+YEARS="23 24"
 @
 
 \item [[COURSE_CODE_ORG]] is a space-separated list of Canvas-to-GitHub