The number of residences for sale has climbed to 83, another record, continuing a trend since the summer. A year ago, 63 houses were offered on the Multiple Listing Service. The median house asking price is $1.695 million; the average is $2.059 million, down $50,000 from the $2.1 million average a month ago. In the past month, the number of land listings has increased from 192 to 195. Condominiums offered for sale have risen from 21 to 25.