Final answer:
The revocation of statutory dual agency varies by state, with no single year applicable nationwide. However, for the Defense of Marriage Act, the U.S. Supreme Court found it unconstitutional in 2013.
Step-by-step explanation:
The question regarding when statutory dual agency was revoked does not have a universally applicable answer because real estate laws and regulations, including those pertaining to agency relationships, are governed at the state level in the United States. Each state has its legislation and timelines for legal changes.
However, if this question pertains to a specific state, that information would be necessary to provide an accurate answer. On the other hand, a factual response to another legal matter is that the U.S. Supreme Court ruled the Defense of Marriage Act unconstitutional in the year 2013. This was a pivotal decision in the progress towards equal marriage rights for same-sex couples in the United States.