How many same-sex couples have married in La Plata County Colorado?

None. The clerk of this County is among those in Colorado who have declined to issue marriage licenses to same-sex couples, presumably pending a ruling by either the Colorado State Supreme Court or the United States Supreme Court either upholding or reversing rulings by lower courts that have struck down Colorado's ban on same-sex marriage as unconstitutional. Meanwhile, some other Colorado counties have been issuing marriage licenses to same-sex couples with judicial approval.