“Where they exist, official statistics tend to understate the number of incidents.” “In most countries, the absence of effective systems for recording and reporting hate-motivated violence, or ‘hate crimes,’ against LGBT persons masks the true extent of violence,” noted a United Nations report last year.

Though clearly widespread, and far from confined to recent decades, violent attacks rooted in gender or sexuality are difficult to quantify. history, which saw 49 people gunned down this weekend at a gay nightclub in Orlando, Florida.

The list of well-publicized murders of gay, lesbian, bisexual and transgender people now includes victims of the worst mass shooting in U.S.