The city of Boston conducted its 38th annual homeless census Wednesday night, and early indications show a slight downward trend in the number of people living on the streets in Boston and using services such as emergency shelters and transitional housing.

Overnight numbers are still being compiled and won’t be available for a few weeks, but Lyndia Downie, president and executive director of the Pine Street Inn — the city's largest homeless shelter — says they’ve seen slight improvement based on previous census figures.

“From 2016 to 2017, the numbers went down slightly," she said. "We were down, I think, 5 percent for individuals and I think about 4 percent for families.”

The census is part of a yearly count of individuals living on the street and includes homeless adults, and families in emergency shelters, transitional housing and domestic violence programs. The 2017 census counted 6,327 homeless people in the city. The census is conducted by about 300 volunteers, and covers the city neighborhoods, Logan Airport, and the transit and park systems.

According to Downie, mental health issues, substance abuse, and lack of affordable housing leads to homelessness. She says Boston is working to shelter the homeless, especially during the cold months.

“This problem isn't going to go away if we can’t have some housing interventions," she said. "For other people, they just need help with a bridge, they're just having a rough patch in their life, and they’re out of work.”

Homeless census data is sent to the federal Housing and Urban Development department (HUD), and also helps the city better understand who they're serving and where the gaps are in services.