It's been a wild real estate ride for many areas in the country, some areas seeing unusually high appreciation. But that may be about to change.

"Home price appreciation has just been very, very strong in the last five years, prices have gone up 83 percent in five years in the Pacific region, they've gone up 70.3 percent in New England," says Beth Haiken, Assistant VP of Public Relations for PMI Group, the second largest mortgage insurance company in the US.

But the Economic and Real Estate Trends report recently released by PMI Group, identifies six housing markets as having a more than 50 percent chance of a housing price decline in the next two years.

Just one quarter ago, there were only two regional markets in this position. Nationwide the report predicts a 21.3 percent chance of a housing price decline. That's slightly up from last quarter's report which predicted a 20 percent chance.

The top 10 states at risk of a housing price decline in the next two years according to the PMI Group report are: California, Minnesota, Michigan, New York, New Jersey, New Hampshire, Massachusetts, Rhode Island, Connecticut, and Maryland.

"What we saw is that risk continues to be concentrated in the coastal areas, which has been true for a while and that in those coastal areas there were some pretty big moves," says Haiken.

Especially on the west coast where six of the top 10 riskiest areas for a housing price decline are in California, they are grouped as follows: San Diego/Carlsbad/San Marcos ranked third, San Jose/Sunnyvale/Santa Clara, Santa Ana/Anaheim/Irvine, Oakland/Fremont/Hayward, San Francisco/San Mateo/Redwood City, and Riverside/San Bernardino/Ontario.

The report takes housing price information from the Office of Federal Housing Enterprise Oversight, employment data from the Bureau of Labor Statistics and the Affordability Index measures constructed by PMI Group.

"We look at home price data -- where [prices] have been, how much have they appreciated and how quickly. We look at labor market data, including employment growth and the unemployment rate, and then we look at affordability -- how much does it cost to pay for the median priced home and what percentage of a typical income [is needed to buy] in that area. If those three things are in balance, which they need to be in order to form that equilateral triangle, then risk in an area tends to be fairly low," explains Haiken.

She adds that when one or more of the legs of the equilateral triangle gets out of balance, risk goes up.

Increasing the risk in many of these areas is the fact that many homeowners stretched their budgets by using interest-only loans and piggyback mortgages in order to qualify and get into their houses.

"The thing that those products have in common, whether it is an interest-only loan or a piggyback mortgage with a home equity line of credit second, is that they transfer risk to the consumer, particularly interest rate risk," says Haiken.

She says that homebuyers are wise to always consider long-term effects of a loan.

"These are all good products ... . But we encourage people to think about what is the right product for them over time and how much risk is appropriate for them to take on. People should think long-term rather than short-term because real estate is a significant investment. For most Americans it's still the biggest investment they'll make and for a lot of people it's the biggest nest egg that they have going into retirement," says Haiken.

However, as with any statistics, what you glean from them depends on how you view them.

Haiken uses this example, "In Boston, which tops our list, there is a roughly 55 percent chance of a price decline. The flip side of that is that there is a 45 percent chance that prices won't decline in the next two years."

She also points out that the index does not attempt to predict the length of a decline or the severity of the decline in housing prices.

Making the list for the top 10 least risky states for a predicted housing price decline are: Washington, Idaho, Wyoming, Utah, New Mexico, North Dakota, Oklahoma, Arkansas, Mississippi and Alabama.