Question: When did Nissan, the Acura Legend maker and the top selling car brand open US assembly plants?

Knowledge 1: List of best-selling automobiles
While references to verify the manufacturers' claims have been included, there is always the possibility of inaccuracy or hyperbole. Also note that a single vehicle can be sold concurrently under several nameplates in different markets, as with for example the Nissan Sunny; in such circumstances manufacturers often provide only cumulative units sold figures for all models. As a result, there is no definitive standard for measuring units sold; Volkswagen has claimed its Beetle as the bestselling car in history as it did not substantially change throughout its production run. By contrast, Toyota has applied the Corolla nameplate to 11 generations since 1966, which have sold over 40 million through July 2013. [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: List of best-selling automobiles
While references to verify the manufacturers' claims have been included, there is always the possibility of inaccuracy or hyperbole. Also note that a single vehicle can be sold concurrently under several nameplates in different markets, as with for example the Nissan Sunny; in such circumstances manufacturers often provide only cumulative units sold figures for all models. As a result, there is no definitive standard for measuring units sold; Volkswagen has claimed its Beetle as the bestselling car in history as it did not substantially change throughout its production run. By contrast, Toyota has applied the Corolla nameplate to 11 generations since 1966, which have sold over 40 million through July 2013. [SEP] Knowledge 2: Infiniti J30
The Infiniti J30, or Nissan Leopard J Ferie in Japan, was a rear wheel drive luxury car. The J30 went into production on April 7, 1992 as a 1993 model to replace the M30 (which was a coupe), and was launched in the United States after its competitor, the Lexus GS. The car was designed to slot between the smaller G20 and the larger Q45, as Infiniti's first mid-size sedan to compete directly with the Acura Legend. Also, it was fairly small but featured rounded styling uncharacteristic of the crowded executive car class, that is now reminiscent of a four-door coupé. Chief designer for the J30 was Jerry Hirshberg, president of Nissan Design International (NDI) and exterior designer Doug Wilson in 1988-1989. Design work was frozen in 1989. In a promotional video produced in 1994, it was referred to as a "personal luxury sedan" as attempt to define it as a four-door coupé. It has the round looks of the Nissan Altima/Bluebird U13. [SEP] Knowledge 3: Infiniti Q45
The Infiniti Q45 is a full-size luxury car which was sold by Nissan's Infiniti brand from 1989 until 2006. It is a rear wheel drive, four-door sedan powered by a V8 engine. Early generations were based on the automaker's Japanese-market flagship sedan, the Nissan President, while models produced after 1996 were based on the slightly smaller Nissan Cima. Exports of the Q45 ceased after 2006, but the Cima continued to be sold in Japan until August 2010, when production of both the Cima and President ended.
Knowledge 1: List of best-selling automobiles
While references to verify the manufacturers' claims have been included, there is always the possibility of inaccuracy or hyperbole. Also note that a single vehicle can be sold concurrently under several nameplates in different markets, as with for example the Nissan Sunny; in such circumstances manufacturers often provide only cumulative units sold figures for all models. As a result, there is no definitive standard for measuring units sold; Volkswagen has claimed its Beetle as the bestselling car in history as it did not substantially change throughout its production run. By contrast, Toyota has applied the Corolla nameplate to 11 generations since 1966, which have sold over 40 million through July 2013. [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.

Answer: 1981