diff --git a/sql/21_datafile.sql b/sql/21_datafile.sql
index 97bc1b5..7bf6bf0 100644
--- a/sql/21_datafile.sql
+++ b/sql/21_datafile.sql
@@ -16,8 +16,8 @@ COL online_status format a15 head "Online Status"
 SELECT  
        file_id, file_name, tablespace_name, 
        round(bytes/1024/1024,0) bytes,  
-       round(maxbytes/1024/1024,0) maxbytes, 
-       round(100*bytes/maxbytes) Pct_Used,
+       round(maxbytes/1024/1024,0) maxbytes,
+       round(100*bytes/CASE WHEN maxbytes = 0 THEN 32767*1024*1024 ELSE maxbytes END) Pct_Used,
        online_status,
        status, autoextensible
   FROM dba_data_files