Labor Day marks many things: the unofficial finish of summer for some, the beginning of the school year for others.

But originally the first Monday in September was set aside to honor those “who from rude nature have delved and carved all the grandeur we behold,” according to Peter McGuire, general secretary of the Brotherhood of Carpenters and Joiners and a cofounder of the American Federation of Labor in New York City, credited by some with starting the holiday in 1882.

And on this, the 135th observance of the holiday, the number of people laboring in southwest Pennsylvania is growing, especially in Butler County.

The July seasonally adjusted unemployment rate in the seven-county Pittsburgh Metropolitan Statistical Area (Allegheny, Armstrong, Beaver, Butler, Fayette, Washington and Westmoreland counties) decreased two-tenths of a percentage point to 4.9 percent, according to figures released by the Pa. Bureau of Labor and Industry.

Within the Pittsburgh MSA, Butler County clocked in with the lowest unemployment rate at 4.3 percent, while Fayette County had the highest rate of the seven counties at 6.5 percent.

Sunita Mondal, associate professor of economics in the School of Business at Slippery Rock University, said, “Cranberry is included in the Butler County, which is thriving in business opportunities with companies like PPG Architectural Coatings moving into the area.

“These contribute to additional job growth in the Butler County region, thus lowering the unemployment rate,” said Mondal.

“The best way to spur new job growth is to work with local businesses, which seems to be working very well for the county,” said Mondal.

She noted that lower property taxes in the Cranberry region attract residents, many of whom commute to Pittsburgh.

Mondal said, “With more people moving into the Cranberry area, local businesses are growing and in turn hiring locals.”

“The job market is growing overall in regards to the Pittsburgh MSA. In July seasonally adjusted nonfarm jobs increased by 3,600 and for the year they were up 5,800,” said Sandy Hoffman, industry and business analyst with the Center for Workforce Information and Analysis with the state Department of Labor.

“What we do look at is 11 industry groups over the year,” said Hoffman. “Three have declined with manufacturing showing the biggest volume decline: 2,500 jobs from July of 2016.

“Government jobs were the second-largest decline: 1,700 jobs, and mining and logging had a decrease of 300,” she said.

“This isn't a surprise because we are seeing this statewide, the decline in these three industries,” said Hoffman.

In the Pittsburgh MSA, Hoffman said, “Construction, information and other services added 400 jobs in the area, and then all remaining industries added at least 1,500 jobs over the year.”

Mondal said, “Butler County's initiatives and focus on infrastructure building including recreational opportunities are reasons for stronger economic growth as well.

“With the building of facilities such as the UPMC Lemieux Sports Complex and Dick's Sporting Goods Sportsplex, the county continues to draw sporting events which contributes to the job growth,” Mondal said.

She said Butler County's proximity to Pittsburgh and the easy access to Interstate 79 and the Pennsylvania Turnpike also contribute to its economic success.

State Labor Department figures put the number of nonfarm jobs in the seven-county area in July at 1,168,600. Over the year, jobs in the MSA increased 0.5 percent (5,800), while statewide jobs grew 1 percent.

And the labor force in southwestern Pennsylvania is showing increases in some interesting areas.

Crunching the numbers, Hoffman said, “The older work force, those 65 and plus, has shown significant growth in the last five years. But eventually they will drop out of the labor force as they retire and leave a big gap.”

Also, Mondal said, the job categories are an important factor. If you look at the top employers in the county as of the last quarter of 2016, educational services (along with health care) comprise a substantial proportion, with the Butler School District, Seneca Valley School District and the State System universities.

“These jobs tend to be more stable over time and could help explain the lower unemployment rates,” Mondal said.

“Lower unemployment could also simply mean more people are leaving the work force,” she noted.

“Hence it is important to look at the trend in the rates, as well as how labor force participation has changed over time.

“According to data from the Census Bureau, labor force participation rate (the percentage of people who are a part of the labor force, either employed or actively seeking employment) between 2011-2015 has been at 64.6 percent (higher than all surrounding counties) and very close to that of Allegheny (64.4 percent),” she said.

This indicates more people in Butler County are a part of the labor force, which further enhances the growth prospects of the region, Mondal noted.

Here’s a look at what Butler County’s jobless numbers say about the region. Numbers were current as of July 1, 2016:Employment in the region is growing steadily at just under 1 percent (0.93 percent), between 2014-2015Employment growth occupations: administrative, sales, management, business and financial operations, education, training and library, health practitioners and food and servicesShrinking industries: Manufacturing (in particular, leather and allied products, petroleum and coal products, machinery, transportation and equipment), utilities, real estate rental and leasingThe median age is 42.7 years (slightly higher than Allegheny County at 41 years), lower than surrounding counties, with 18 percent of the population over the age of 65. This is lower than surrounding counties and the same as Allegheny CountyPercentage of people age 25+ years with a bachelor’s degree or above (between 2011-2015) stands at 32.3 percent, higher than all neighboring counties except Allegheny (37.8 percent)Source: Census Bureau Quick Facts