D.C. police made 22 arrests in 18 robberies this past week, including a 12-year-old boy suspected in four different cases, police said in a news release.

Of those arrested for robbery in the past week, more than 70% were teenagers. D.C. has seen an uptick in unarmed robberies in 2019, according to data from D.C. police.

While armed robberies are down nearly 10% compared to last year, unarmed robberies are up, with 1,347 incidents since the start of 2019 compared to 1,100 for the same period of time in 2018. That’s an increase of more than 20%.

But this is also the first time in seven years the number of unarmed robberies has increased; in 2012, there were 2,485 incidents, nearly two times as many for the same time period this year.

Since the beginning of the decade, the number of unarmed robberies has dropped dramatically. The number of armed robbery has fluctuated, but generally dropped over the decade, from 1,462 in 2009 to 677 in 2019.

Check out the interactive graph below to see year-over-year numbers for the past decade.