Relative popularity of premillenialism, postmillennialism and amillennialism in North America (excluding Catholics and Orthodox)? There has been some discussion on SE about the differences between the various schools of eschatological thought surrounding the 1000 years ('the millennium') described in Revelation chapter 20. I am interested in the relative popularity of these different views amongst North American Christians who are not Catholic or from one of the Eastern Orthodox churches (since these groups are well documented in terms of populations, and have always been amillennialist in outlook).

While some have made claims along the lines of, e.g., "school X has been hemorrhaging members for the last 20 years" etc, this is usually tendentious. I have found it very difficult to find actual statistics and other hard facts about the numbers of adherents these four-ish schools below (premillennialism itself could be divided up and counted as five separate schools of their own!) and their sub-categories have, and how they are changing over time relative to each other:


preterism: considers that all events discussed in Revelation (and the rest of the NT) have already occurred historically, and the 1000 years does not refer to any future events. Common amongst some mainline Protestant groups.
premillennial dispensationalism: considers that believers will be gathered up to heaven in a rapture which could occur at any moment, following which 7 years of tribulation will occur, followed by the Second Coming which will precipitate 1000 literal years of Jesus' rule on earth. This has four sub-categories: pre-Tribulation, post-Tribulation, mid-Tribulation and pre-Wrath, based on differing views about the timing of the rapture in relation to the tribulation. Particularly popular amongst conservative Evangelical groups. 
historic premillennialism: same as above, but does not posit a separation between church and the Jewish people, and little emphasis on different 'dispensations' or particular time periods wherein God works differently. Popular amongst a variety of groups. 
postmillennialism: the 1000 years is a general description of the post-Resurrection world, where the church will continue to increase until the entire world gradually becomes the Kingdom of God, whereupon the Second Coming will occur. No rapture. A common view amongst Calvinist groups and Christian Reconstructionists, but not limited to them. 
amillennialism: the 1000 years is symbolic and does not refer to any actual time period, and there is no rapture, just the Second Coming only. The standard view of Christianity (both Western and Eastern), until the Protestant Reformation. It is still the standard in Catholicism and Orthodoxy, and some mainline Protestant groups.


Can anyone provide any information as to (1) the (rough) numbers of people who support these various views today, and (2) whether these populations have changed significantly over the last 30 years, say since 1980 and (3) what the major drivers possibly underlying such changes could be? (E.g., premillennial dispensationalism was extremely popular across all of North America during the early 20th century [linked to the Scofield Reference Bible], and had another spike in appeal during the 60s and 70s [aided by the Arab-Israeli wars], but seems to have declined since then - perhaps, since my info is anecdotal at best).
I don't believe that a comprehensive answer to this question is possible at this time.
Many denominations refrain from even identifying a preferred eschatological position, let alone require their adherants to support it, so adherence statistics won't cut the mustard. To answer the question properly would require professional surveying on eschatological views. The organization most likely to do have done this is the Pew Research Centre, and they don't seem to have been asking the specific questions that would pin down a person's views sufficiently; the closest related questions that I could find that they have been asking are:

Do you believe in the second coming of Jesus Christ--that is, that Jesus will return to earth someday, or don't you believe this? -- Pew Forum on Religion &amp; Public Life/Pew Research Center for the People &amp; the Press Survey, Jul, 2006

and

Some people say that the state of Israel is a fulfillment of the biblical prophesy about the second coming of Jesus. Do you believe that this is true, or not? -- Pew Forum on Religion &amp; Public Life/Pew Research Center for the People &amp; the Press Survey, Jul, 2003  &amp; 2006

These questions are not only insufficient to pin down eschatological views into the desired categories, but they haven't been maintained within their annual survey.
This leaves more ad hoc surveys with questionable sampling methods, like this one that gives figures for Evangelicals:

A majority of evangelical leaders believe that Jesus Christ will return to earth and then reign with his followers for 1,000 years, a new survey shows.
This end times theology is called premillennialism and 65 percent of surveyed evangelical leaders identify with it.
As part of its monthly poll, the National Association of Evangelicals surveyed its board of directors, which include the CEOs of denominations and representatives of a broad array of evangelical organizations, on their eschatological beliefs.
&quot;It’s in our human nature to want to prepare ourselves – physically, emotionally, spiritually – for what might be ahead,&quot; said NAE President Leith Anderson.
The poll, released this week, found that 13 percent of those surveyed are amillennialists – believing that the non-literal millennial reign of Christ is happening now as Christ reigns at the right hand of the Father.
Four percent believe Christ's second coming will occur after the 1,000-year period during which the nations will be progressively converted to Christianity. This is postmillennial theology.
Seventeen percent, meanwhile, identify with &quot;other&quot; end times theology.
-- Christian Post, Poll: What Evangelical Leaders Believe about the End Times, Christian Post Reporter Audrey Barrick, March 9, 2011 (emphasis added)