diff --git a/pivot-table.el b/pivot-table.el
index d10d5bb..3f7bdb2 100644
--- a/pivot-table.el
+++ b/pivot-table.el
@@ -44,11 +44,11 @@ TODO: more documentation"
   "Extract the column names from a table"
   (let (result)
     (dolist (row source)
-      (unless (and (listp row) (eq "!" (car row)))
+      (when (and (listp row) (equal "!" (car row)))
         (let ((n 2))
           (dolist (cell (cdr row))
-            (unless (eq cell "")
-              (setq result (((format "%s" cell) . n) . result)))
+            (unless (equal cell "")
+              (push (cons (format "%s" cell) n) result))
             (setq n (1+ n))))))
     result))