Murders in the US rose by 30% from 2019 to 2020, according to FBI data released on Monday. The surge represents the biggest year-to-year increase that has been seen since such records began being kept in the 1960s.

There were a total of 21,570 murders in 2020, an increase of approximately 4900 in 2019. About 77% of those murders were committed with a firearm, a slight increase from 74% in the previous year.

Multiple cities, including Albuquerque, Milwaukee, Memphis, and Des Moines, have recorded record high murder rates.

Major crimes, however, decreased overall for 2020, though violent crime – including assault and rape – still increased overall by 5%.

The number of murders, however, has not hit its peak, with the ‘90s still representing record highs. A total of 25,000 murders were recorded in 1991, for instance. New York City and Los Angeles also accounted for more than 10% of murders nationally in 1990, but account for less than 5% today. Both cities still saw slight increases in their murder rates from 2019 to 2020, however, with New York City going from 319 to 500 and Los Angeles moving from 258 to 351.

The FBI itself has not given their own analysis of the change, though experts have pointed to the Covid-19 pandemic, as well as civic unrest in major cities during 2020 as potential reasons for an increase in violence.

The data for 2020 is also somewhat incomplete as only about 16,000 of the eligible 18,619 law enforcement agencies submitted their full data.

Major cities have continued reporting increases in murder rates in their cities in 2021. A mid-year report by the Major Cities Chiefs Association found that homicides this year are running higher than the same time last year, signifying another potential increase for 2021.