Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_87 (year_of_intro VARCHAR, name__designation VARCHAR, primary_cartridge VARCHAR, country_of_origin VARCHAR, type VARCHAR)

### Question ###
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?

### Accurate 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"