CREATE TABLE table_name_87 (year_of_intro VARCHAR(255), name__designation VARCHAR(255), primary_cartridge VARCHAR(255), country_of_origin VARCHAR(255), type VARCHAR(255))
What is the total number of Year of Intro(s), when Country of Origin is Soviet Union, when Type is Reusable, when Primary Cartridge is 40mm, and when Name/ Designation is RPG-29?
    
SQL: SELECT COUNT(year_of_intro) FROM table_name_87 WHERE country_of_origin = "soviet union" AND type = "reusable" AND primary_cartridge = "40mm" AND name__designation = "rpg-29"