Question: The 9mm German designed submachine gun used by OMEGA was developed in what decade?

Context paragraphs:
M56 Submachine gun: The M56 submachine gun is a Yugoslavian submachine gun chambered in 7.62×25mm Tokarev, designed for use with the Yugoslav People's Army.  Initially a state-funded product, it was later produced by Zastava Arms and saw use in a number of conflicts following the breakup of former Yugoslavia.  The M56 is a clone of the MP 40 submachine gun used by Nazi Germany, easily distinguished from the MP 40 by its increased length and curved magazine.

Heckler &amp; Koch MP5: The Heckler & Koch MP5 (from German: "Maschinenpistole 5" , meaning "Submachine gun 5") is a 9mm submachine gun of German design, developed in the 1960s by a team of engineers from the German small arms manufacturer Heckler & Koch GmbH (H&K) of Oberndorf am Neckar.  There are over 100 variants of the MP5, including some semi-automatic versions.

JS 9 mm: The JS 9 mm () is a commercial export version of the QCW-05 (with the exception of different chambering.)  It is a suppressed submachine gun developed by the Jianshe Industries (Group) Corporation of Chongqing.  The JS 9 mm is capable of using any 9×19mm round, including the popular 9×19mm Parabellum round but has specifically been chambered for the indigenous, armour-piercing 9×19mm DAP92-9 round.

.380 ACP: The .380 ACP (9x17mm) (Automatic Colt Pistol) is a rimless, straight-walled pistol cartridge developed by firearms designer John Moses Browning.  The cartridge headspaces on the mouth of the case.  It was introduced in 1908 by Colt, for use in its new Colt Model 1908 pocket hammerless semi-automatic, and has been a popular self-defense cartridge ever since, seeing wide use in numerous handguns (typically smaller weapons).  Other names for .380 ACP include .380 Auto, 9mm Browning, 9mm Corto, 9mm Kurz, 9mm Short, 9×17mm and 9 mm Browning Court (which is the C.I.P. designation).  It is not to be confused with .38 ACP, 9mm Ultra, 9×18mm Makarov, 9×19mm Parabellum nor the rimmed .380 Long Revolver CF & .380 Rook Rifle cartridges, introduced around 1870.

MCEM 2 submachine gun: MCEM-2 (Machine Carbine Experimental Model 2) submachine gun was produced only in prototype form, but was one of the very first submachine guns to combine wrap-around bolt and magazine in pistol grip, features later copied in the Czechoslovak Sa vz.  23, Israeli Uzi and a great number of other submachine guns.  MCEM-2 was the second prototype in a line of experimental submachine guns, designed in Britain in 1944.  It was envisioned as a possible replacement for the STEN submachine gun then in service.  The MCEM-2 was developed by Jerzy Podsedkowski, a Polish constructor involved in work on Vis and Mors, who fled from occupied Poland to Britain.  It is believed that prototypes of MCEM-2 were made before the end of WW2, and its derivatives MCEM-4 and MCEM-6 were tested soon after the war.  The latter modifications differed mostly in adoption of the rate-reducing mechanism, incorporated into trigger unit; the rate of fire therefore was decreased from 1000 to more realistic 600 rounds per minute.  Nevertheless, neither prototype was found suitable for adoption, and several years later British army adopted a more conventional submachine gun, the Sterling-Patchett.

OMEGA (counterterrorism unit): OMEGA is the premier counter-terrorism unit of Latvia.  Founded in 1992, OMEGA cooperates with many other counter-terrorism units over the world.  Its equipment and weaponry includes the Heckler & Koch MP5, the HK G36C and the Walther P99.

Arsenal submachine gun: The Arsenal M23 submachine gun (Estonian: "Arsenali püstolkuulipilduja" ) (also known as Arsenal Tallinn) was an Estonian submachine gun from 1926 through 1935.  These submachine guns were designed and produced in the Estonian military equipment factory "Arsenal" in Karjamaa, Tallinn, but production was not more than 600 units.  The weapon was chambered for the 9x20 mm semi-rimmed Browning cartridge to be compatible with ammunition for the Browning FN M1903 pistol which had been adopted by the Estonian Army.  It operated on the blowback system and was essentially similar to the MP18.1; having a wooden stock, slotted barrel jacket, and horizontal left side magazine feed.  A uniquely slender 40 round single column box magazine led to frequent cartridge feeding problems; and cooling fins which were machined lengthwise along the barrel to promote cooling air flow when firing (similar to the Lewis machine gun), unnecessarily complicated production.  It was used by the combat support units of the Border Guard, the Estonian Defence League and the Estonian Defence Forces.  The Arsenal submachine gun was replaced in Estonian service by the Finnish Suomi KP/-31 submachine gun in 1938.  The Estonian Army sold a few samples to Latvia and all of the remainder found their way to Republican forces during the Civil War in Spain.

Jatimatic: The Jatimatic is a Finnish 9 mm submachine gun developed in the late 1970s and early 1980s by Jali Timari.  The submachine gun made its debut in 1983.  The Jatimatic was manufactured in very limited numbers (approx. 400) initially by Tampereen Asepaja Oy of Tampere and later—Oy Golden Gun Ltd (as the GG-95 PDW, re-introduced unsuccessfully in 1995).  The firearm was designed primarily for police, security forces and armored vehicle crews.  It was never adopted into service by the Finnish Defence Forces, although the later GG-95 PDW version was tested by the FDF in the 1990s; the conclusion of the tests was that the GG-95 was not suitable as a service weapon.

KP m/44 submachine gun: The KP m/44 ("Konepistooli malli 1944", English: Submachine gun, model 1944 ), nicknamed "Peltiheikki" or "Pelti-kp", which could be translated as "sheet-metal Heikki" and "sheet-metal machine pistol"/"sheet-metal submachine gun" respectively, was a Finnish 9mm copy and modification of the Soviet mass-produced 7.62 mm submachine gun PPS-43.

M2 Hyde: The Hyde-Inland M2 was a United States submachine gun design submitted for trials at Aberdeen Proving Ground in February, 1941.  Work was undertaken by General Motors Inland Manufacturing Division to develop workable prototypes of George Hyde's design patented in 1935.  The model first submitted for trials in April 1942 was designated the "Hyde-Inland 1".  Trials revealed the design was superior to the M1 submachine gun in mud and dirt tests, and its accuracy in full-automatic firing was better than any other submachine gun tested at the time.  An improved "Hyde-Inland 2" was designated U.S. Submachine gun, Caliber .45, M2 as a substitute standard for the M1 Thompson in April, 1942.  As Inland's manufacturing capacity became focused on M1 carbine production, the US Army contracted M2 production to Marlin Firearms in July, 1942.  Marlin began production in May 1943.  Marlin's production failed to match the trials prototype performance; and Marlin's original contract for 164,450 M2s was canceled in 1943 upon adoption of the M3 submachine gun.  The M2 is chambered for the .45 ACP cartridge and used the same 20- or 30-round magazine as the Thompson.  Its cyclic rate of fire is 570 rounds per minute.  None of the approximately 400 manufactured were issued by any branches of the United States military.

Supporting paragraphs: OMEGA (counterterrorism unit) Heckler &amp; Koch MP5
Answer: 1960s