Complex sentence: Stateless individuals in Greece have had difficulty receiving social services like health care and education and--until December 1997--were denied the protection of the 1954 U.N. Convention Relating to the Status of Stateless Persons, which Greece ratified in 1975.
Split into simpler sentences: Stateless individuals in Greece have had difficulty receiving social services like health care and education. Until December 1997, they were denied the protection of the 1954 U.N. Convention Relating to the Status of Stateless Persons, which Greece ratified in 1975.