To update my post from almost 11 months ago, https://www.google.com/intl/en/ipv6/statistics.html
shows the geometric growth in IPv6 has leveled off somewhat. It was 9% at the beginning of 2016, and it looks like it finish the year around 14 or 15%. (I'm not sure how to interpret the spread in the graph, so maybe it's best to use the middle.) IPv6 is showing steady growth for sure.
Not shown, and perhaps what is most important to Veeam, is the percentage of IPv6 nodes that do not have IPv4 available.
I hope everyone who can't use Veeam because of lack of IPv6 will continue to post.