The rate that Hamilton's house prices have been rising when compared to a year ago has been declining rapidly since the summer.

In a national index published Wednesday by Teranet and National Bank, Hamilton home prices were up by the third-largest percentage after Victoria and Vancouver in November, compared to the previous November.

But year-over-year gains in Hamilton have fallen precipitously during the second half of 2017, the index shows.

In June, Hamilton's prices were up 25.6 per cent year-over-year. 

But since that summer peak, gains have been cut in half. 

Hamilton prices were up 12.3 per cent year-over-year in November.

The above graph shows the amount by which home prices have changed in a particular month compared to the same month a year earlier, expressed as a percentage. Move along the graph lines to see the individual month percentage changes.

The steep drop tracks that of Toronto, which saw a year-over-year gain of 29.2 per cent in June, and in November was down to a 10.7 per cent year-over-year gain.

In the same time period, the national 11-city index has also fallen, but not as sharply. The national index has gone from a 14.2 per cent year-over-year gain in June to a 9.2 per cent year-over-year gain in November.

The Teranet-National Bank Composite house price index looks at price changes in the same house over time in 11 cities. The overall index rose 9.2 per cent from November 2016, which was the smallest year-over-year gain since June 2016.

Looking monthly, Hamilton's reading on the index has been falling for three straight months after reaching a peak in August.

It was also the third straight decline for the national index, and the largest drop for any November outside of a recession, according to National Bank economist Marc Pinsonneault.

kelly.bennett@cbc.ca