In the trades (roofing, plumbing etc) the increase appears to be a few percentages every quarter. In the hospitality sector (restaurants & pubs) the numbers are far more compelling.
One of our clients' will surpass the halfway mark in the next few months (mobile vs. desktop visits.) What's of real value to the hospitality crowd, is that 79% of the website's New Visit ratio came from Mobile, this is phone, not phone & tablet (in this case.)
Studies on SERPs behavior on smart phones have become established research. I came across an image that will be of interest to those of you who are investing in SEO and hoping to understand how the eye guides the click.
The Image for this post shows two scenarios. The heat signatures are actually where the user's eye is tracking. With hot spots indicating time spent in that area of the smart phone screen.
You can see in the first image (left) the eye concentrates on what's called the Knowledge graph (images and any relevant editorial content Google decides to serve on the subject of the Search.)
The eye does not go much further. If you were a business selling 'Louvre' guide books, you would need to appear in the top three results to secure decent traffic.
In this particular case, the Search for 'Louvre' serves up a knowledge graph that is relevant and the mobile user's eye/search is satisfied.
In the second image, the heat signatures show you what the eye does when the knowledge graph is irrelevant to the users query. You see the eye, dropping down, scanning more results in search of a listing that will answer his/her need.
To sum up the this post, please do a search for your own business on a smart phone, be sure to use generic keywords for which you could (ideally be found), then take a look at the amount of real estate that exists.
Make note of where you would have to rank in those listings in order to secure organic traffic.
If you haven't the slightest idea of what I am talking about, give us call.
SEO and how it works on mobile is a conversation well worth having.
Check out the full Mobile Viewport study here http://justinbriggs.org/how-do-users-interact-with-serps-on-mobile-devices