Amateur radio postage stamps

The excellent Southgate Amateur Radio News page today mentioned that Luxemburg is bringing out a postage stamp to commemorate the 75th anniversary of the Luxemburg radio society. See http://www.southgatearc.org/news/march2012/amateur_radio_stamp_for_luxembourg.htm .  This got me wondering how many other countries have issued stamps with an amateur radio theme? I recall the USA doing a ham radio stamp in the mid-1960s.

Wondering if there were others I did a search on Google images for amateur radio postage stamps. Interesting.