Pitcairn Islands
noun: Pitcairn Islander(s)
adjective: Pitcairn Islander

Poland
noun: Pole(s)
adjective: Polish

Portugal
noun: Portuguese (singular and plural)
adjective: Portuguese

Puerto Rico
noun: Puerto Rican(s) (US citizens)
adjective: Puerto Rican

Qatar
noun: Qatari(s)
adjective: Qatari

Reunion
noun: Reunionese (singular and plural)
adjective: Reunionese

Romania
noun: Romanian(s)
adjective: Romanian

Russia
noun: Russian(s)
adjective: Russian

Rwanda
noun: Rwandan(s)
adjective: Rwandan

Saint Helena
noun: Saint Helenian(s)
adjective: Saint Helenian