A New York-based nonprofit research group says 100,000 fewer job advertisements were posted online in March and the drop has resulted in a decline of over 1.1 million advertised vacancies in the last four months.

The Conference Board’s monthly Help-Wanted Online Data Series measures the number of new online jobs and openings reposted from the previous month on more than 1,200 major Internet job boards and smaller Web sites that serve niche markets.

The March decline follows a modest drop of 6,600 ads in February, but the figure is much better than the record drops of 507,000 and 506,000 in December and January. Online job ads have declined over 25 percent since November.

“The March numbers indicate that we are not at the bottom of the employment cycle but that the declines in labor demand may be slowing,” Gad Levanon, senior economist at The Conference Board, said this week in a news release. “The next two months, April and May, are when employers typically ratchet up their spring hiring.”

There are about 3.25 million ads and slightly over two advertised vacancies for every 100 people in the labor force.

The downward trend in employer demand coupled with the monthly increases in unemployment is creating a widening gap in the supply and demand balance in most states and making it increasingly difficult for the unemployed to find jobs, the group said.

Mississippi is one of five states with over six unemployed people for every advertised vacancy. Michigan (8.37) had over eight unemployed people for every advertised vacancy, followed by Indiana (6.70), Kentucky (6.66), Mississippi and North Carolina (6.46).

Michigan’s jobless rate was 12 percent in February, the highest in the country. And despite the high ratio of unemployed people for every advertised vacancy, the number of online job ads were up slightly in Michigan last month.

“Usually, when things begin to get better they don’t get better everywhere at once. They get better in pockets,” Conference Board economist June Shelp said Wednesday.

“Standing up and predicting which way it’s going at this juncture, in my mind, is a little tough. I think that if you look at the overall national picture and you look at what we have been kind of seeing…it does look a little bit better.”

But no state had fewer unemployed persons than advertised vacancies.

California had the largest overall decline in online job ads — 19,800.

There were 365,500 online ad vacancies for management positions in March, a decline of 173,000 or 32 percent from March 2008, according to The Conference Board’s data.

For 55 years, the research group released a print job advertising index, which had a long history of predicting employment levels, Shelp said. The online jobs data index began in 2005.

“The next two months…will tell the tale a lot better,” Shelp said.