Right this moment I'm not clean, but this is a fairly rare occurrence. I use only maybe once a month at most. Longest time clean since I first started using was, idk, I think 6 months when I first went off to my ill fated stint in college, and during that time I was straight up clean-clean, using nothing...and I was absolutely miserable, it was the lowest point of my life, probably even lower than when I was a homeless junkie. Although these days I'm also scripted suboxone and adderall and I drink occassionally, so I probably don't fit many people's definition of clean even most of the time.
However I'm not entirely sure of exact numbers. Maybe I'm crazy, but counting clean time like it's super important makes no sense to me. It's a meaningless number. My goal is to not have drugs control my life. I don't care if I was clean for 10 years, if I spent every day obsessing over drugs and being on the edge of a full blown relapse and needing to go to NA meetings 3 times a day to try to stave off my incessant ravenous desire to get high to me I would've still absolutely failed in my goal, drugs would still own me. However, if I never went a week without using and somehow in this hypothetical situation the drugs weren't screwing up my life or controlling me I'd be happy with it. The latter situation is highly, HIGHLY unlikely though...but not because using in and of itself would be the issue, but because a person doesn't go out of their way to use that often unless they have an issue. In fact, keeping track of clean time for me would actually seem counter-productive; it promotes an unhealthy all or nothing mentality that frames borderline inevitable slip ups as immense failures that erase all the work a person did up to that point.