diff --git a/embddr/gnuplot.scm b/embddr/gnuplot.scm
index fb7d8f7..77f424f 100644
--- a/embddr/gnuplot.scm
+++ b/embddr/gnuplot.scm
@@ -66,7 +66,10 @@
             (lambda ()
               (for-each
                (cut >> <>)
-               (map (lambda (sample) (string-join (map (cut format #f "~a" <>) sample) " "))
+               (map (lambda (sample) (string-join (map
+                                              (lambda (x) (number->string
+                                                      (exact->inexact x)))
+                                              sample) " "))
                     (apply zip (cons ((first plots) 'x)
                                      (map (lambda (plot) (plot 'y)) plots)))))))
           (close-port file-port)