I thought that this presentation was worth a share. This was Marcus Tober, the founder of SearchMetrics and presented at SMX in June 2014.
It is always interesting to see these aggregate level mass studies observing and observing over time the variable that may effect ranking.
Take a read.
Since I am not a company in the UK or non-geographically a company I have decided not to use my ccTLD or TLD and just be in the UK.
Plus, my previous .co.uk site had gotton out of control, needed major updates, maintenance, and since I had never done any link building but had comment (legitimately) on many sites, [IMHO] was unfairly hit by Google.
In short, ditched the site, annually more expensive hosting and finally moved the site.