Since figures were tallied in June, Google +1 has risen from 3.5 percent adoption to 4.5 percent, a 28 percent increase. In terms of button presence on the home page of the top 10k sites measured, Google +1 has already surpassed the Twitter tweet button plugin in web popularity
http://searchenginewatch.com/article/2092682/Google-1-Button-on-More-Homepages-than-Tweet-Button