John’s note: We often talk about religious demographic changes including changes the growth of Christianity either in absolute terms of percentage terms. This is used as a comparative religion tool.
If a religion is growing quickly or holds a large market share then we have a reason to believe it may be more valid compared to an idea with a small or declining share, due to the economics of information.
We do not, however, often use that same tool to compare denominations inside of Christianity. While most or all Christian denominations have important things in common, there are also important differences. Some data on Christianity even becomes questionable when groups which are arguably non-Christian, such as Mormons, are included.
This data indicates that the largest numerical growth as a percent between 1990 and 2008 in the U.S. belongs to non-denominational Christians, Evangelical Christians, and Atheists (including agnostics), respectively.
Seems like the market favors conservatism, Christianity, and more logically rigorous worldviews at a higher propensity after all.