#+NAME: tasks-TABLE
#+BEGIN_SRC emacs-lisp :exports results :colnames '("TODOs" "DONEs" "Percent")
(setq todo (apply '+ (org-map-entries (lambda () 1) "/TODO")) )
(setq done (apply '+ (org-map-entries (lambda () 1) "/DONE")) )
(setq percent (/ done (+ done todo)) )
( list '(todo done  percent ))
#+END_SRC

#+RESULTS: tasks-TABLE
| TODOs | DONEs | Percent |
|-------+-------+---------|
| todo  | done  | percent |