Window Snyder, Mozilla Chief Security Officer has announced in the Mozilla Security blog that the time to deploy security vulnerability patches has improved 25% since last year.
The results come from comparing how long it took to deploy patches to 90% of users. Firefox 22.214.171.124 to 126.96.36.199 took about 8 days. The latest update from 188.8.131.52 to 184.108.40.206 took just 6 days, in large part due to improvements in infrastructure according to the blog post.
It would be interesting to know what sample was used to gather the results.