What is the most used referencing style?

I’m looking into changing the citation style my publication uses and would like to find out what the most used harvard-type style is. Anyone know how I can find this out?

That is a laudable goal!  but I haven’t got a clue.  In science, we always go with that of Cell, when left to our own devices. 

I don’t know what the most common one is, but I have long been impressed with the Chicago Manual of Style (from which Turabian is an offshoot apparently), which is a widely-used style.

CMS provides flexibility of application across a range of disciplines (from footnoting Arts to author-date science layout), and has an excellent (well-worded and comprehensive) manual.

Wikipedia has an article about it, which will give you some idea and of course key links: http://en.wikipedia.org/wiki/The_Chicago_Manual_of_Style