Mark Zuckerberg testifies before the House Energy and Commerce Committee in the Rayburn House Office Building on Capitol Hill April 11, 2018.

Facebook shares have whipsawed in the past year, falling from close to $220 last summer to a low around $125 in early 2019 before climbing back to near-$190. But one thing has remained constant: the percentage of small businesses that buy Facebook advertisements.

As Facebook rolls out a series of new tools in the attempt to bring more small businesses into its advertising mix, it is a minority of Main Street businesses that say they advertise on Facebook, and at a level that is not showing growth or retreat, according to the CNBC|SurveyMonkey Small Business Survey for the second quarter.