(CNN) -- Gay couples can now legally marry in 18 countries -- a statistic that increasingly raises an important question: Where's the best spot for a same-sex honeymoon?

With same-sex marriage legal for several years now, millions of gay, lesbian and trans couples are adding a honeymoon to their wedding plans. As recently as 2014, only about 55 percent of same-sex couples went on a honeymoon after their wedding ceremony, according to Community Marketing & Insights (CM&I), a San Francisco-based market research firm that tracks LGBT travel trends.