How many first-author papers should I publish during postdoc to get a tenure-track faculty position? I'm currently a 2nd year postdoc in mechanical engineering field working on bio-related applications. I have ~9 first-author papers during my Ph. D., but have not been able to publish a first-author paper during postdoc. 
For anyone in a similar situation (postdoc in mech. working on bio stuff), what is the reasonable number of 1st author papers to apply for TT? If I have several non first-author papers, would that still "count" as my research output when getting reviewed by the search committee?
I think quality of the work is more important than number or papers.  Even more important than first-author status.  

Of course non-first-author papers count; for exapmle, get the actual first author to write one of your recommendation letters, to describe your contribution to the research.