Not very often. I've worked in the system a long time, and I think there's room for improvement in most of the quality of the section 84 releases. I can only comment on my experience, and I worked with the Parole Board prior to this. There were a lot more good-quality section 84 releases.
How often does that happen? I guess you'd have to ask the higher-ups for the stats, and I'm sure they'd provide them to you, but good section 84 releases take time and they're resource-driven.
There's also not a lot of knowledge, I think, among front-line parole officers as to how to go about doing that. There's protocol to be followed; you don't just phone or email. You should be going there in person, presenting protocol to the community, building relationships with the community, before you're asking them to accept an offender back. It takes time. It's resource-driven, and I think there's room to improve the expertise that goes along with a section 84 release.