Your hunch is correct: Southern California is more crowded, as the region’s population has passed 18 million with the fastest growth rate since 2014.

Los Angeles, Orange, Riverside and San Bernardino counties as of July 1 had added a combined 128,552 residents to 18.03 million, according to new data from the state Department of Finance. That’s up from 94,828 new neighbors in the previous year.

According to my trusty spreadsheet, it was a year that saw Los Angeles County add the most people while an ongoing trend continued to the east as the Inland Empire experienced the fastest growth. Meanwhile, fewer departed the region and foreign immigration cooled modestly.

Look at the comings and goings of locals in percentage-point terms: Last year’s four-county population increase was 0.72 percent higher than 2016. That growth rate was an improvement from the 0.53 percent increase in the previous year. Still, the region’s population growth has been in a long-running deceleration.

Recent additions are historically slow, running below the annual average expansion rate of 0.83 percent seen since 2000. And four-county growth has trailed the statewide pace for 12 consecutive years. In the past year, California added 300,816 residents — 0.77 percent growth — to 39.61 million as of July 1.

Plus, there’s a painful reality in the numbers. A key force behind the past year’s regional population increase is part of an overarching challenge: As fewer people leave, the shortage of housing deepens.

Southern California combined for 64,953 of “net domestic outmigration.” That’s demographer talk for the number of people leaving a geographic region — whether it be to elsewhere in California or to another state — vs. the number of folks moving in. That’s down from 86,367 similar relocations the year before.

Despite all the tough talk about curtailing immigration from the Trump administration, 85,339 foreigners relocated to the four-county region in the past year, down slightly from 86,367 in 2016, but above the 74,000 average inflow seen since 2010.

It’s worth noting that the four-county region we here at the Southern California News Group call Southern California is home to four of the state’s five most populous counties.

Los Angeles County was tops at 10.27 million; Orange County ranked No. 3 with 3.2 million; Riverside County, at 2.39 million, ranked No. 4; and San Bernardino County at 2.16 million was fifth. (FYI: Just down the freeway San Diego ranked No. 2 at 3.3 million.)

In 2017, Los Angeles County added the most residents — 56,689 — in the region. But while L.A.’s growth rate (0.55 percent) was its best in three years, it ranked 14th among the state’s 15 most-populous counties.

L.A. saw fewer exits: Its 58,489 net domestic move-outs were down from 80,494 in 2016. Still, that loss exceeded the 55,783 who arrived via foreign immigration. More births than deaths also helped grow the population.

Riverside County ranked second in Southern California for new residents: up 30,135 or 1.28 percent. That was the second-fastest growth among California’s large counties and Riverside’s best since 2014.

Riverside also was the only county in the region to enjoy a domestic influx — a net 9,813 arrived from elsewhere in the U.S., up from 7,117 in 2016. Immigration added a net 6,285 vs. 6,361 more foreigners in 2016.

The 2017 population trends also follow another long-running trend: Folks are moving eastward to cheaper, newer housing. In the 1970s and 1980s, the Inland Empire accounted for one-third of the region’s new residents. Since then, Riverside and San Bernardino counties have been home to nearly half of the population growth in Southern California.

In the past year, Orange County added 21,626 people or 0.68 percent. Yes, it’s a bounce up from 2016’s nine-year low, but it ranked just 11th among the state’s 15 big counties and is roughly three-quarters of the average post-recession growth rate. This slowdown is likely linked to the county’s high cost-of-living.

Fewer people exited the county, too, as its 13,972 net domestic exits were down from 18,977 in 2016. Foreign net immigration also fell to 17,568 vs. 17,779 in 2016.

And San Bernardino County added 20,102, a 0.94 percent jump — its best since 2011 and sixth fastest among the big counties. Move-outs dropped considerably: 2,305 vs. net domestic outmigration of 7,505 in 2016 while foreign arrivals of 5,703 were virtually unchanged from 2016.

This relatively slow population growth helps explains how the region’s job market ended up short of workers.

In the three years ended July 1, state jobs figures show bosses in the four-county region added 539,000 jobs. Yet population only grew by 347,000. So, the region’s jobless rate fell to just above 4 percent from roughly 7 percent in the period.

Slowing population growth isn’t just a regional trend. U.S. population growth hasn’t been above 1 percent a year since 2001, and its growth was similar to Southern California, up 0.7 percent at last reading. Basically, the nation is aging and kids aren’t having as many kids as they used to. Controversial immigration is helping fill in the shortfall.

Now, a critic of the local economic climate could complain that not too long ago — around the turn of the century — the combined population of the four counties grew at nearly twice the pace as it did in the last four years. And Southern California’s 2.3 percent-a-year population growth pace of the 1980s, or 1.3 percent average of the 1990s, are distant memories.

A pragmatist — perhaps a commuter who is regularly stuck on Southern California’s congested roadways or a frustrated house hunter — might counter that logic with a simple retort: “If the region could grow faster, where would we put all those extra people?”