To make the averages more accurate, ZIP codes with fewer than 30 home sales per year were not included in The Buffalo News' real estate sales analysis.
At least one real estate professional would have liked the number of sales to be even higher.
"When you get up to sales of 100 (homes), it's quite accurate," said Dan Symoniak, general manager for Stovroff Realty, the area's largest home seller. "Below that, I'm a little skeptical."
One problem is that property values in some neighborhoods vary wildly within the same ZIP code. Stately mansions are a few streets away from abandoned homes.
"When you have that type of disparity in property values, you're more likely to get price swings from one year to another," Symoniak said.
ZIP codes with close to 30 sales a year where prices rose since 1998 in Erie County were 14204 and 14208 (Buffalo's East Side), 14033 (Colden) and 14080 (Holland). In Niagara County, sales rose in 14012 (Sommerset/Barker), 14067 (Hartland/Royalton), 14105 (Hartland/Middleport) and 14172 (Wilson).
Home sale prices fell in these areas with close to 30 sales: 14201 and 14202 (Buffalo's Allentown section), 14025 (Boston), 14069 (Concord/Glenwood), 14070 (Gowanda/Collins) and 14303 (Niagara Falls/Town of Niagara).