Question: When did the maker of Acura Legend, the owner of Scion, and Nissan open US assembly plants?

Knowledge 1: Scion (automobile)
Scion is a discontinued marque of Toyota that started in 2003. It was designed as an extension of its efforts to appeal towards younger customers. The Scion brand primarily featured sports compact vehicles (primarily badge engineered from Toyota's international models), a simplified "pure price" model, and eschewed trim levels in favor of offering a single trim for each vehicle with a range of factory and aftermarket options for buyers to choose from to personalize their vehicle. The "Scion" name, meaning the descendant of a family or heir, refers both to the brand's cars and their owners. The brand first soft launched in the United States at selected Toyota dealers in the state of California in June 2003, before expanding nationwide by February 2004. In 2010, Scion expanded into Canada. In an effort to target the generation Y demographic, Scion primarily relied on guerrilla and viral marketing techniques. [SEP] Knowledge 2: 1973 oil crisis
Some buyers lamented the small size of the first Japanese compacts, and both Toyota and Nissan (then known as Datsun) introduced larger cars such as the Toyota Corona Mark II, the Toyota Cressida, the Mazda 616 and Datsun 810, which added passenger space and amenities such as air conditioning, power steering, AM-FM radios, and even power windows and central locking without increasing the price of the vehicle. A decade after the 1973 oil crisis, Honda, Toyota and Nissan, affected by the 1981 voluntary export restraints, opened US assembly plants and established their luxury divisions (Acura, Lexus and Infiniti, respectively) to distinguish themselves from their mass-market brands. [SEP] Knowledge 3: Acura Legend
The Acura Legend is a mid-size luxury/executive car manufactured by Honda. It was sold in the U.S., Canada, and parts of China under Honda's luxury brand, Acura, from 1985 to 1995, as both a sedan, which was classified as a full-size car, and a coupe, which was classified as a mid-size car (similar to how the Honda Accord is set up today). It was the first flagship sedan sold under the Acura nameplate, until being renamed in 1996 as the Acura 3.5RL. The 3.5RL was the North American version of the KA9 series Honda Legend.
Knowledge 1: Scion (automobile)
Scion is a discontinued marque of Toyota that started in 2003. It was designed as an extension of its efforts to appeal towards younger customers. The Scion brand primarily featured sports compact vehicles (primarily badge engineered from Toyota's international models), a simplified "pure price" model, and eschewed trim levels in favor of offering a single trim for each vehicle with a range of factory and aftermarket options for buyers to choose from to personalize their vehicle. The "Scion" name, meaning the descendant of a family or heir, refers both to the brand's cars and their owners. The brand first soft launched in the United States at selected Toyota dealers in the state of California in June 2003, before expanding nationwide by February 2004. In 2010, Scion expanded into Canada. In an effort to target the generation Y demographic, Scion primarily relied on guerrilla and viral marketing techniques. [SEP] Knowledge 2: 1973 oil crisis
Some buyers lamented the small size of the first Japanese compacts, and both Toyota and Nissan (then known as Datsun) introduced larger cars such as the Toyota Corona Mark II, the Toyota Cressida, the Mazda 616 and Datsun 810, which added passenger space and amenities such as air conditioning, power steering, AM-FM radios, and even power windows and central locking without increasing the price of the vehicle. A decade after the 1973 oil crisis, Honda, Toyota and Nissan, affected by the 1981 voluntary export restraints, opened US assembly plants and established their luxury divisions (Acura, Lexus and Infiniti, respectively) to distinguish themselves from their mass-market brands. [SEP] Knowledge 3: Acura ZDX
The Acura ZDX is a mid-size luxury crossover SUV developed by Honda for its upmarket brand Acura. The car was originally scheduled to be called the Acura MSX. The ZDX debuted at the 2009 New York International Auto Show on April 8, 2009. The vehicle was also the first to be completely designed at Acura's southern California design studio in Torrance.
Knowledge 1: Scion (automobile)
Scion is a discontinued marque of Toyota that started in 2003. It was designed as an extension of its efforts to appeal towards younger customers. The Scion brand primarily featured sports compact vehicles (primarily badge engineered from Toyota's international models), a simplified "pure price" model, and eschewed trim levels in favor of offering a single trim for each vehicle with a range of factory and aftermarket options for buyers to choose from to personalize their vehicle. The "Scion" name, meaning the descendant of a family or heir, refers both to the brand's cars and their owners. The brand first soft launched in the United States at selected Toyota dealers in the state of California in June 2003, before expanding nationwide by February 2004. In 2010, Scion expanded into Canada. In an effort to target the generation Y demographic, Scion primarily relied on guerrilla and viral marketing techniques. [SEP] Knowledge 2: 1973 oil crisis
Some buyers lamented the small size of the first Japanese compacts, and both Toyota and Nissan (then known as Datsun) introduced larger cars such as the Toyota Corona Mark II, the Toyota Cressida, the Mazda 616 and Datsun 810, which added passenger space and amenities such as air conditioning, power steering, AM-FM radios, and even power windows and central locking without increasing the price of the vehicle. A decade after the 1973 oil crisis, Honda, Toyota and Nissan, affected by the 1981 voluntary export restraints, opened US assembly plants and established their luxury divisions (Acura, Lexus and Infiniti, respectively) to distinguish themselves from their mass-market brands. [SEP] Knowledge 3: Acura RLX
The Acura RLX is a full-size luxury sedan manufactured by Honda and sold under their Acura division, released in 2013. Succeeding the Acura RL, the RLX offers two versions, a front-wheel drive base model equipped with Acura's Precision All-Wheel Steer (P-AWS) four-wheel steering system, and a hybrid variant featuring SH-AWD that serves as Acura's flagship. The JDM version, the Honda Legend, is only offered with the SH-AWD powertrain.

Answer: 1981