Context : The BRDM-2 (Boyevaya Razvedyvatelnaya Dozornaya Mashina, Боевая Разведывательная Дозорная Машина, literally ``Combat Reconnaissance/Patrol Vehicle'') is an amphibious armoured patrol car used by Russia and the former Soviet Union. 
Subject : BRDM-2 
Relation : service entry
What was the year BRDM-2 entered service?