Over the last year Google has brought us a whole zoo full of changes to search. We have had the Panda updates and then there was the Penguin.
There have been stories written about Google only showing 7 results instead of 10 per page
Danny Sullivan wrote: It looks as if Google is testing a move away from showing the traditional 10 listings to only displaying seven, and it also appears that it’s even easier than ever for one site to dominates all those results.
The game keeps changing and you need to keep up. Annexcore put out a piece on local search factors that is worth looking at. Its also worth reading the blog post they wrote which details some of the points made in the infographic.