You get around a LOT!!
Here is a more detailed response as to why I believe that the majority of Protestants do not attend a regular bible study, adult classes or small groups.
From:
http://hirr.hartsem.edu/research/fastfacts/fast_facts.html#attend
Q: How many people go to church each Sunday?
A: For years, the Gallup Research Organization has come up with a consistent figure — 40 percent of all Americans, or roughly 118 million people, who said they attended worship on the previous weekend. Recently, sociologists of religion have questioned that figure, saying Americans tend to exaggerate how often they attend. By actually counting the number of people who showed up at representative sample of churches, two researchers, Kirk Hadaway and Penny Marler found that only 20.4 percent of the population, or half the Gallup figure, attended church each weekend.
As added proof for the accuracy of this smaller percentage of churchgoers, if 20.4% of Americans (approximately 63 million in 2010) attended the nation’s 350,000 congregations weekly then the average attendance would be 180 people per congregation which is almost exactly the figure that numerous research studies have found.
So 40% of all Americans attend a church. Just working off of that figure, further research as stated above, shows that roughly half of all Christians actually go to church. Even if every single one of those Christians attended an adult class in addition to the worship service, the split would be close to 50/50. But, from my observations an even smaller percentage (roughly 20 percent) attend anything beyond the basic worship service.