The time it takes to write a paper is directly proportional to the quality of the information you have to report. It takes forever to write a paper around a weak set of research data analysis that does not illustrate a clear contribution. Whereas, when the output answers the research question with authority, it takes very little effort to describe the contribution and in most cases it requires fewer words. With a solidly supported conclusion, I can write a first draft in 4 to 8 hours. When the conclusion is tenuous, then it takes at least 5 times as long and will probably not result in an acceptance by a decent journal.
It ultimately works out only as 2 to 3 papers every year as sending , modifying resending to various journals take lot of time when compared to writting alone..
I give less time can do much better ...
Original papers also depend on the work load you have n what prime center you are working at ...you need to wait long to collect substential data ,unless you are into a multicentric project