I would go to latter, not the former. I don't think 8.5% mechanical margin is sustainable for extended period of time. I think, we've had these in the past where they jump in and out, we always say look back 12 months, and that gives you every three or four quarters, it gives you a pretty good idea, how we're performing. We've said for a long time anywhere from 6% to 7.5% mechanically is pretty good performance. I guess we ticked that up to 6.5% mechanically, which is pretty good as a baseline to seven. Anyhow maybe 7.5%, we are finishing jobs. These are going better than expected. Electrically, we've been performing at these levels for a long time, those sectors are led by people that really know how to cut cost when they need to, not, how to meter back in the cost, a lot of it happens upfront, right? We don't have big write-offs typically, may be we have them every three or four years. Usually, most of it's not our fault, and we do a pretty good job recovery sometimes. A third at any given time might be our fault, and so, we do a good job, avoiding badness. I always say margins are driven by and absence of that is an executing or good work when you have it. So that funnel upfront is very important and we have been very careful right now, on the kind of job we're selecting, and at the beginning of this COVID thing, people were like getting a little desperate, we then participate, and we've seen more normal fitting resume. So yes, longwinded answer to normalize margins, these are a little high right now for mechanical, but you know, I look back 12 months we are doing okay. Mark?