I've seen that poster listed as being first printed in 1929 and also as first appearing for the 1932-33 elections - don't know which is correct? It also appears on the cover of Peter Adam's book, "Art of the Third Reich." - no details there either, just the image.
If you check out Hohlwein on www.google.de you'll find the "Und Du?" poster for sale, should you be so inclined ... lots of his other images, too.
