The percentage increase in condo sale prices in North Conway is a number you could get from a local Realtor. But condos in North Conway span quite an array of dwellings, from smallish time-shares to quarter shares, to half shares to the generally appealing full ownership of a 2-4 bedroom row house to free standing homes in a Condo development. So if you want numbers that are solid, you should compare apples with apples--and not all condos against all condos over a 5 year period.
Also, and just because I have been doing this for a long time, I recall there was a time you couldn't give condos away. And so the pricing at that point would be artificially low--i.e. would not represent even what the replacement cost would have been. My recollection is that the condo debacle was from 1989 through perhaps 1997. Meaning that the increase in value you will see from 1997-2002--which will certainly be impressive--may NOT reflect the same growth in appeal or in value that houses experienced, but will be a rapid return to normalcy.