The quote underneath symbolises how the Soviet era t-72 entered service on the front line.
“Although the Soviet T-72 entered service in 1973, this tank (and its upgraded alternatives) remained in the front-line service in 41 nations throughout the 1990s and into the 21st century. These included Soviet-built domestic-use, Soviet-built export, and other nation licensed-production tanks.” (p.23)
This quote also states that even post Soviet Era, the T-72 (and its upgraded counterparts) remained in service as a reliable front line force.