If you start on December 2008 and end in May 2012, it is much easier to see the trend. I agree that it is an exaggeration to say rapid, but it does look like a

If you start on December 2008 and end in May 2012, it is much easier to see the trend. I agree that it is an exaggeration to say rapid, but it does look like a definite downward trend for desktop and upward for mobile.