The city of Atlanta has experienced its largest single-year population gain in more than 35 years, while the 10-county metro Atlanta area now has more people than 24 states, according to the annual report of the Atlanta Regional Commission for 2007.

The Atlanta region’s population passed the 4 million mark last year, after a 104,000-person increase between April 1, 2006 and April 1, 2007. The region is now home to 4,029,400 people.

The region had 3,429,379 residents in 2000, 2,557,800 in 1990, 1,896,182 in 1980 and 1,500,823 in 1970.

During the last three years, the region has added nearly 315,000 new residents. Since 2000, the Atlanta region has added, an average of almost 86,000 net new residents every year, which is a greater increase than the average annual increase for 44 states.

The region’s average increase of 86,000 people a year since 2000 has almost reached the 87,000 person per-year pace set during the 1990s, a period of unprecedented growth.

The city of Atlanta’s growth also remains strong according to the ARC. The city received its largest single-year population gain in more than 35 years, adding 12,600 people. The city had lost almost 80,000 residents between 1970 and 2000. But from 2000 to 2005, the city has added more than 25,000 new residents, an average of 5,125 people a year. For the last two years, however, the city has more than doubled that pace, averaging more than 11,000 new residents each year.

Atlanta now has 464,200 residents, compared with 416,474 in 2000, 415,200 in 1990, 424,992 in 1980 and 495,039 in 1970.

Due in part to the strong growth in Atlanta, Fulton County led the region in population growth last year, adding 33,400 new residents. Fulton is still the largest county in the metro area, with an estimated population of 933,600. After averaging 14,521 new residents each year in the 1990s, Fulton has jumped past that growth pace this decade, averaging 16,800 new residents each year since 2000.

Neighboring Gwinnett County is second with a population of 740,200. For years, Gwinnett led the region in population growth, and its 20,600 increase the past year shows Gwinnett’s growth is still strong, the ARC said. Cobb County’s 9,800-person increase to 664,700 residents puts it third in the region.