In 2019, there were various types of hate crimes reported, including those motivated by race, religion, sexual orientation, ethnicity, and other factors. The least frequently occurring category generally tends to be those motivated by sexual orientation or gender identity, although the specific counts can vary by report.
According to the FBI's Hate Crime Statistics for 2019, hate crimes motivated by sexual orientation were reported less often than those motivated by race or religion. For example, roughly 16.7% of all reported hate crimes were based on sexual orientation, which translates to a smaller numeric count compared to other categories.
To get the most precise figure, it would be best to refer to the specific FBI report or statistics for 2019, which provides detailed breakdowns of hate crimes by category and percentage.