Existing-home sales showed some improvement in February, but remain constrained by low inventories of homes for-sale that are pushing price growth to the fastest pace in a year, according to the National Association of Realtors.

The median existing-home price for all housing types was $202,600 in February – 7.5 percent higher than a year ago.

"Insufficient supply appears to be hampering prospective buyers in several areas of the country and is hiking prices to near unsustainable levels," says Lawrence Yun, NAR’s chief economist. "Stronger price growth is a boon for home owners looking to build additional equity, but it continues to be an obstacle for current buyers looking to close before [mortgage] rates rise."

Mortgage rates, for now, continue to hover near historical lows. The 30-year fixed-rate mortgage averaged 3.71 percent in February, according to mortgage giant Freddie Mac.

"With all indications pointing to a rate increase from the Federal Reserve this year – perhaps as early as this summer – affordability concerns could heighten as home prices and rents both continue to exceed wages," says Yun. Indeed, an NAR study earlier this month found a widening gap between rent and income growth across the country, which is making it more difficult for renters to become home owners.

4 Stats to Gauge the Market

Here are some more findings from NAR's latest housing report:

1. Existing-home sales: Existing-home sales rose 1.2 percent month-over-month, reaching a seasonally adjusted annual rate of 4.88 million in February. Sales are 4.7 percent higher than a year ago.

2. Housing inventory: Housing inventories rose 1.6 percent to 1.89 million existing-homes for-sale in February, but remain 0.5 percent below a year ago. Unsold inventory is at a 4.6-month supply at the current sales pace. Most economists consider a 6-month supply healthy for the market.

3. Distressed sales: Foreclosures and short sales comprised 11 percent of sales in February, down from 16 percent a year ago. In February, 8 percent of sales were foreclosures, and 3 percent were short sales. On average, foreclosures sold for a discount of 17 percent below market value (in January, it was 15 percent) and short sales were discounted by 15 percent on average (from 12 percent in January).

4. Days on the market: Properties were on the market for 62 days, on average, in February, down from 69 days in January. Short sales were on the market for the longest – 120 days. Foreclosures tended to sell in 58 days and non-distressed homes took 61 days. Thirty-four percent of homes sold in February were on the market for less than a month, according to NAR’s report.

By Region

The following is an overview of how sales fared in February across the country:

Northeast: existing-home sales plunged 6.5 percent to an annual rate of 580,000, but are 3.6 percent above year ago levels. Median price: $241,800, up 3.3 percent year-over-year.

Midwest: existing-home sales were mostly unchanged from January at an annual level of 1.08 million, but are 4.9 percent higher than February 2014 levels. Median price: $152,900, up 8.8 percent from a year ago.

South: existing-home sales rose 1.9 percent to an annual rate of 2.11 million last month, and are 6 percent higher than year ago levels. Median price: $177,900, up 8.5 percent from a year ago.

West: existing-home sales increased 5.7 percent to an annual rate of 1.11 million in February, and are 2.8 percent above a year ago. Median price: $290,100 -- 4.2 percent above February 2014.