Home price appreciation continued to grow steadily during the middle of Spring selling season, according to the S&P/Case-Shiller Home Price Indices released Tuesday morning. The data released covers activity during April 2016.

The national index, covering all nine census divisions, posted a 5.0% annual gain from April 2015, while the 20-City Composite and 10-City Composite posted a increase year-over-year of 5.4% and 4.7%, respectively. Not seasonally adjusted, all three portions of the index edged up from March levels. After seasonal adjustment, the National Composite went up by a scant 0.1% month-over-month, while 10-City Composite and 20-city Composite gained 0.3% and 0.5%, respectively. Among the cities in the 20-City Composite (after seasonal adjustment), 15 cities experience home price gains between March to April, compared to only six cities last month.

"The housing sector continues to turn in a strong price performance with the S&P/Case-Shiller National Index rising at a 5% or greater annual rate for six consecutive months,” said David M. Blitzer, Managing Director and Chairman of the Index Committee at S&P Dow Jones Indices, in a statement. Although April's results represent fairly stable, continued strength, Blitzer did express some concerns about housing in the coming months.

"The outlook is not without a lot of uncertainty and some risk. Last week’s vote by Great Britain to leave the European Union is the most recent political concern while the U.S. elections in the fall raise uncertainty and will distract home buyers and investors in the coming months/ The details in the S&P/Case-Shiller Home Price data also hint at possible softness. Seasonally adjusted figures in the report show that three cities saw lower prices in April compared to only one city in March."

Aside from a limited supply of homes on the market that has contributed to price appreciation, "the home price increases reflect the low unemployment rate, low mortgage interest rates, and consumers’ generally positive outlook, " noted Blitzer. "One result is that an increasing number of cities have surpassed the high prices seen before the Great Recession. Currently, seven cities – Denver, Dallas, Portland OR, San Francisco, Seattle, Charlotte, and Boston – are setting new highs."

Among all census regions, the Pacific Northwest and the West continue to be the strongest markets, led by . The Northeast and Upper Mid-West regions, however, were at the other end of the ranking.

Cities with the largest year-over-year price gains are: