The “recent years” x-axis selection only gave you the last seven years (2001-2007 at the time of writing) which didn’t let you monitor trends very far back in time. The new “recent (odd) years” choice gives you the last seven odd-numbered years, which obviously go back further. Why do we use the odd years? Well we’re avoiding “2000″ because this text on a web page refers to the actual year much less than, say “2001″.
You can use Compare Stuff to monitor trends in public interest of any topic through time – either by day of the week, recent months or recent years. Here’s a comparison of “gun crime” vs. “serious fraud” over recent years: