Question: How many countries use the export version of the third generation main battle tank that went into service in 1980 ?

text: List of main battle tanks by generation
Third generation
The third generation of main battle tanks is characterized by composite armour and computerized stabilized fire control systems , which allow firing on the move as well as very high first hit probability on targets up to 2,000 meters away .
Main battle tanks are often classified as belonging to a particular generation, although the actual definition and membership in these generations is not clearly defined. Soviet and Russian military planners organize tanks with first generation of tanks up to 1945, and four generations of main battle tanks[Note 1] while Canadian strategists organize main battle tanks into three generations. [Note 2] The military of the People's Republic of China also recognizes three generations of its own tanks. In 1983, Rolf Hilmes saw three tank generations and three intermediate generations, which consisted mainly of upgraded vehicles. The first generation of main battle tanks were based on or influenced by designs of World War II, most notably the T-34 and the Panther tank. The second generation was equipped with NBC protection (only sometimes), IR night vision devices, a stabilized main gun and at least a mechanical fire control system. The third generation is determined by the usage of thermal imagers, digital fire control systems and special (composite) armour. However, Hilmes acknowledged that tanks cannot be definitively grouped by generations, as each tank-producing country develops and introduces its tanks in tune with its own ideas and needs. He also states that breakdown of postwar tanks by generations is based on timeframe and technical factors, as a basis for further discussion.
Name In service from Origin Notes
T-80 1976 Soviet Union World 's first turbine engine equipped tank . Though the Swedish Stridsvagn 103 that entered service in 1960s used a turbine engine alongside a diesel . However , T-80 in Hilmes 's book is very different to a T-80 in real world , and early models of the T-80 offer no big differences compared to T-64A in overall performance . So models prior to the T-80B should be regarded as Second generation intermediate
Leopard 2 1979 West Germany Replaced Leopard 1
MBT-80 1979 United Kingdom Prototype , never entered service
M1 Abrams 1980 United States Replaced M60 Patton
FV4030/4 Challenger 1 1983 United Kingdom Replaced FV 4201 Chieftain
AMX-40 1983 France Prototype , never acquired by the French Army
M-84 1984 Yugoslavia A Yugoslav variant of the soviet T-72
EE-T1/EE-T2 Osório 1986 Brazil Prototype , never acquired by the Brazilian Army
K1 88-Tank 1988 United States / South Korea First Main Battle Tank in use with the Republic of Korea Armed Forces , developed by Hyundai Precision ( later Hyundai Rotem )
Merkava Mark III 1989 Israel As of 2016 , the Merkava III is by far the most numerous tank in frontline IDF service . Compared to the Merkava II , it has upgrades to the drivetrain , powertrain , armament , and electronic systems . The most prominent addition was the incorporation of the locally developed IMI 120 mm gun
Type 90 Kyū-maru 1990 Japan Replaced Type 74
Ch'onma-ho 215/216 1992 North Korea A further development of Ch'onma-Ho
AMX Leclerc 1993 France Replaced AMX 30
Zulfiqar I/II/III 1993 Iran Iranian tank derived from T-72 and M60 Patton . Zulfiqar III is the most advanced variant
T-90 1993 Russia Updated version of the T-72 ; originally introduced into service on October 1992 as T-72BU , but simultaneously renamed as the T-90
PT-91 Twardy 1995 Poland A development of the T-72 M1
C1 Ariete 1995 Italy Replaced american tanks
TR-85 1996 Romania First built in 1985 , the modernised TR-85M1 Bizonul ( the bison ) variant was updated in 1996 , as an effort to bring it up to date with other NATO countries . The project was a cooperative effort between Aerospatiale-Matra , Sagem , Kolmorgen-Artus , Racal and Romanian factories , such as ROMARM , METRA , I.O.R . and Aerostar
Stridsvagn 122 1997 Sweden Based on the German Leopard 2
M-95 Degman 1997 Croatia Croatian development of the prototype Yugoslav M-91 Vihor