If it's a plain static site, a day to a week. From my experience, what usually takes longer are the revisions and the amount of time it takes to get back and forth with the client. With revisions, it could take anywhere from 1 week to even 6months (client can't make up his mind on the design and continually adds new content) .
In my experience for the simple static website, I didn't take long time. It's about 1 week. Most of the time I spend for planing the site strategy, site map and then writing contents. Maybe because of I am a web designer & developer so the website development is easy for me. If We can sumarize all of system requirements, we can develope more faster than start building a web by no plainning... however for the big website it will tak long time also for maintance and the e-marketing after finished development.