Dear Presidential Candidate:

By this time, you probably have spent an inordinate amount of time in Iowa and New Hampshire, the first two states to begin picking their presidential delegates.

Whatever your party affiliation, you now probably suffer the illusion that you know those two states very well indeed.

Well, you don't. Not unless you're familiar with the 1987 Statistical Abstract of the United States and the Iowa Poll. Heed some friendly advice from one who is familiar with those two sources: stop and look carefully in both directions before crossing the street, and remember what your mother told you about always wearing clean underwear in case you're in an accident. These are perilous places.

Sure, it's true that both are relatively small, moderately conservative states, an overwhelming majority of whose populations live in small towns and on farms and enjoy relatively low crime rates.

But that's only part of the story, candidate.

Did you know, for one thing, that Iowa has the highest per-capita ownership of motorcycles of any state in the Union and that New Hampshire is second? The Statistical Abstract says that about 9 percent of Iowans and nearly 6 percent of New Hampshirites own motorcycles. Compare that with the national average -- a mere 2.3 percent. (Even in California it's only 2.7 percent.)

Consider what this means, candidate. The population of Iowa is almost 3 million, which means that at any given time there are 270,000 motorcycles streaking through the cornfields or preparing to do so. In New Hampshire, population nearly 1 million, this comes to around 60,000 bikers whizzing up hill and down dale.

Add to this the fact, as revealed in the Statistical Abstract, that New Hampshire has the highest per-capita ownership of autos in the nation. More than three-fourths of its people own cars.

And if that isn't enough, would you like to guess which state has the highest per-capita consumption of beer and distilled spirits in the nation? New Hampshirites consume an average of 51 gallons of beer annually, compared with 34 gallons nationwide. They put away 6.26 gallons of whisky, gin, etc. compared with 2.53 nationwide. A sobering thought, isn't it, candidate, especially in conjunction with the motorcycles?

Iowans, on the other hand, keep their two-wheelers on the straight and narrow. They rank 48th when it comes to swilling the hard stuff and 29th in beer consumption. They also have the second-lowest divorce rate in the nation, 3.6 per 1,000 population.

This is not surprising given the fact that an overwhelming majority of Iowans have a literal belief in heaven and hell, according to the Des Moines Register's Iowa Poll.

One Iowa Poll on the subject a while back indicated that 65 percent of the respondents believed they would go to heaven, while only 5 percent thought they would go to hell and the rest were unsure. Thirty-one percent knew someone they thought would wind up in hell.

This led the Register to speculate that many Iowans who do go to hell never realize it because they think they're in Ottumwa. That observation was inspired by evangelist Billy Sunday, who preached in that community many years ago and afterward remarked that "The only difference between hell and Ottumwa is that Ottumwa has a railroad so you can get out of town." The Register further speculated that if hell were really Ottumwa its male residents would form a Rotary Club and wear name tags that said, "Hello, My Name Is Hideous Fiend."

I know of no similar record of New Hampshirites' belief in heaven and hell, but they do have the Manchester Union Leader, which has traditionally played the role of the demon with the pitchfork for just about every presidential candidate who visits the state, coining such nicknames as "Rocky the Wife-Swapper" (for Nelson Rockefeller), "Jerry the Jerk" (Gerald R. Ford) and "Moscow Muskie." New Hampshire voters also routinely run early leaders such as Muskie, Lyndon B. Johnson, Ronald Reagan, George Bush and Fritz Mondale through the hoops and all the circles of the inferno.

So, gentle candidate, if one day in the near future you're hit by a motorcycle and wake up surrounded not by angels wearing wings but by friendly people wearing name tags, don't panic. You probably won't be in hell, but you just might be in Ottumwa or Dixville Notch.

The writer is a political reporter on The Post's national staff.