I do realise the poll is about using SR to reinforce sobriety but, I'm answering the OP heading 'what percentage of your sobriety is owed to SR'.
I stopped drinking on my own, by using Rational Recovery's 'Addictive Voice Recognition Technique' (with a background of a 20 year daily alcohol addiction; for which I sought relief from a variety of sources, to include working the AA Steps twice to no avail) yet I attribute my sobriety 100% to this site.
The reason being, I'd encountered RR years ago, but never tried AVRT. As a consequence of reading the RR AVRT threads in the Secular Connections part of SR, I started my own thread and then, spurred on, I took a leap of faith and learnt and applied AVRT and made a Big Plan: consequently, I'm no longer a drinker.
Therefore, if I hadn't read SR, I'd never have encountered the proof that AVRT works and would've missed the opportunity to apply it, successfully. Thank you SR and all Secular Connections inhabitants.