A major increase in existing home sales in the Midwest and a more modest boost in the Northeast helped offset declines in other parts of the country, according to the National Association of Realtors.

In its latest update on existing home sales in the United States, the organization says these transactions were proceeding at a seasonally adjusted annual rate of 5.45 million in April. This figure was a year-over-year increase of 6 percent and up 1.7 percent from an upwardly revised pace of 5.36 million for March.

The National Association of Realtors defines existing home sales as completed transactions involving single-family homes, condominiums, co-ops, and townhouses. April was the second consecutive month where existing home sales were up from the previous month. Lawrence Yun, NAR chief economist, says this activity signals an increase in momentum in the housing market.

"Primarily driven by a convincing jump in the Midwest, where home prices are most affordable, sales activity overall was at a healthy pace last month as very low mortgage rates and modest seasonal inventory gains encouraged more households to search for and close on a home," he said. "Except in the West—where supply shortages and stark price growth are hampering buyers the most—sales are meaningfully higher than a year ago in much of the country."

In the Midwest, existing home sales stood at an annual rate of 1.39 million, a 12.1 percent increase from both March and April 2015. The region had the largest year-over-year growth in the median home price, which increased 7.7 percent to $184,200.

The Northeast had the largest year-over-year growth in the annual rate of existing home sales, which was projected to be 740,000. This pace was up only 2.8 percent from March, but was also 17.5 percent above the April 2015 pace. The median home price in the Northeast in April was $263,000, a year-over-year gain of 4.1 percent.

Existing home sales in the South had an annual rate of 2.19 million, down 2.7 percent from March. However, this pace was still a year-over-year increase of 4.3 percent. The median price for an existing home in this region was up 6.5 percent from April 2015 to $202,800.

Median price growth also rose 6.5 percent over the course of the year in the West, reaching $335,000 in April. The annual pace of existing homes, 1.13 million, was down 1.7 percent from March and 3.4 percent from April 2015.

The National Association of Realtors has long cautioned that inventory shortages and rising prices may be deterring some buyers. While the total inventory of 2.14 million existing homes for sale was up 9.2 percent from March, it was 3.6 percent lower than in April 2015. Prices rose from the previous year for the 50th month in a row, with April's median existing home price of $232,500 marking a 6.3 percent gain from April 2015.

"The temporary relief from mortgage rates currently near three-year lows has helped preserve housing affordability this spring, but there's growing concern a number of buyers will be unable to find homes at affordable prices if wages don't rise and price growth doesn't slow," said Yun.

First-time homebuyers may find the ability to get a home to be a little easier in coming months. These buyers accounted for 32 percent of existing home sales in April, up from 30 percent in both March and April 2015. First-time homebuyers also made up an average of 30 percent of existing home sales for 2015 as a whole.

The average commitment rate for a 30-year conventional fixed rate mortgage in April was 3.61 percent, according to Freddie Mac. This rate was down from 3.69 percent in March and at its lowest point since May 2013. It was down from the average rate of 3.85 percent for the year 2015.

The National Association of Realtors says first-time buyers can also benefit from proposed changes to FHA condo rules. Housing and Urban Development Secretary Julian Castro said at a recent NAR expo that these changes are under review by the Office of Management and Budget. These rules would address issues such as the recertification process, owner occupancy requirements, and property insurance limitations.

"Secretary Castro's update that the condo rule changes are in their final stages before implementation received great applause from Realtors both at the forum and throughout the country," said NAR President Tom Salomone. "To ensure that purchasing a condo increasingly becomes a viable and affordable option for first-time buyers, NAR supports the ongoing efforts to eliminate the unnecessary barriers holding back condo sales. We hope that progress on this condo rule means we'll see some much-needed changes in the near future."

Existing homes sold in April typically spent 39 days on the market before they sold. This length of time was unchanged from April 2015, but was down from 47 days in March and at its lowest point since June 2015. Forty-five percent of existing homes sold in April were on the market for less than a month.

Short sales typically took 120 days to close, while foreclosures were listed for an average of 51 days before selling. By contrast, non-distressed homes typically spent only 37 days on the market.

Distressed sales fell for the second month in a row, falling from 10 percent of all existing home sales in April 2015 and 8 percent in March to 7 percent in April. Five percent of sales were foreclosures, while 2 percent were short sales. Foreclosures sold for an average discount of 17 percent, while the typical short sale had a discount of 10 percent.

Twenty-four percent of existing homes sold in April were purchased with cash, unchanged from a year ago and down from 25 percent in March. Individual investors account for most of these purchases, with 69 percent buying a home without financing in April. The share of investors was 13 percent in April, matching a low point set in October 2015; it was down from 14 percent in both March and April 2015.

The sales of existing single-family homes in April posted a seasonally adjusted annual rate of 4.81 million, up 0.6 percent from 4.78 million in March and 6.2 percent higher than the April 2015 pace of 4.53 million. The median single-family home sold for $233,700, a year-over-year increase of 6.2 percent.

Condominium and co-op sales posted a seasonally adjusted annual rate of 640,000 units, up 10.3 percent from the March pace of 580,000 and 4.9 percent from the April 2015 pace of 610,000. The median price for an existing condominium or co-op in April was $223,300, up 6.8 percent from the previous year.