Warning: the way the IPv6 adoption ratio is computed changed on 24 June 2013. More information here.
You can put one of these widgets to link the http://6labs.cisco.com/stats from your site.
The picture in the widgets will reflect the state of the IPv6 in the countries of your choice that you can supply (up to 5) as part of the widget's URL.
If you prefer to serve the widget from your own site to increase the responsiveness, you are welcome to do so. The picture changes every 24 hours, so you can fetch the image once a day and serve from your own server. Please randomize the time when you fetch the widget so that the different requests would not pile up at the same time.
The sample HTML code to display the stats of USA, Japan, France, India and China with hotlink is as follows:
The result looks like this: