Question: Doctor Smooth has a similar flavor to Dr. Pepper which was invented in which decade?

Context articles: Coquito nuts
Crème de menthe
Grains of Selim
Dr Pepper
Diet Dr Pepper
Doctor Smooth
A&amp;W Cream Soda
Dublin Dr Pepper
Doctor Pepper (song)
Fanta Citrus

Coquito nuts are the fruits from a feather-leaved palm, "Jubaea chilensis", native to Chile, having a thick trunk from which is obtained a sugary sap used for making wine and a syrup, and widely cultivated as an ornamental in warm dry regions.
 (Spanish, diminutive of "coco", "coco palm", from Portuguese "côco"; see coconut.)
 Coquito nuts look like miniature coconuts and have a very similar flavor to coconuts.
 They have a brown exterior and a white interior with a hollow center.
 They measure about 1/2 to 3/4 inch in diameter.
 They are completely edible (raw or cooked), and are crunchy, with an almond-like sweetness.
Crème de menthe (] , French for "mint cream") is a sweet, mint-flavored alcoholic beverage.
 Its flavor primarily derives from Corsican mint or dried peppermint.
 It is available commercially in a colorless version (called "white") and a green version (colored by the mint leaves, or by added coloring if made from extract instead of leaves).
 Both varieties have similar flavor and are interchangeable in recipes, except where color is important.
The term Grains of Selim refers to the seeds of a shrubby tree, "Xylopia aethiopica", found in Africa.
 It is also known as kimba pepper, African pepper, Moor pepper, Negro pepper, Kani pepper, Kili pepper, Sénégal pepper, Ethiopian pepper, Hwentea and Guinea pepper.
 The seeds have a musky flavor and are used as a pepper substitute.
 It is sometimes confused with grains of paradise.
 By far the most common name in Wolof is djar in Senegal, and this is how it is listed on most, if not all, Cafe Touba packages.
Dr Pepper is a carbonated soft drink marketed as having a unique flavor.
 The drink was created in the 1880s by Charles Alderton in Waco, Texas and first served around 1885.
 Dr Pepper was first nationally marketed in the United States in 1904, and is now also sold in Europe, Asia, Canada, Mexico, Australia, and South America, as well as New Zealand and South Africa as an imported good.
 Variants include a version without high fructose corn syrup, Diet Dr Pepper, as well as a line of additional flavors, first introduced in the 2000s.
Diet Dr Pepper is a no-calorie Dr Pepper that was first introduced in 1986.
 This version replaces the high fructose corn syrup found in the original with aspartame.
 Diet Cherry Chocolate Dr Pepper (2007–2008) was introduced as a limited edition flavor on November 21, 2007.
 It was discontinued in April 2008.
 It became available in Canada in early January 2008.
 A nondiet version was never created.
 The taste is similar to Canfield's Diet Cherry Chocolate Fudge Soda, but with the distinctive Dr Pepper flavor.
 It was featured in the song "Cherry Chocolate Rain" by YouTube celebrity Tay Zonday.
 Upon ceasing production, it was replaced by Cherry Vanilla Dr Pepper.
Doctor Smooth is a Canadian soda produced by President's Choice.
 With a flavor in the same vein as the American Dr Pepper, Doctor Smooth derives its name from the very little carbonation the beverage possesses.
 A "Secret Recipe" soda.
A&W Cream Soda is a cream soda carbonated soft drink introduced by A&W Root Beer in 1986.
 A&W Root Beer was first sold at a Veterans Day parade in Lodi, California in 1919 and the company established in 1922 by Frank Wright and Roy Allen.
 The first product they created was A & W Root Beer.
 It was not until 1986 that A&W Brands, headquartered in White Plains, N.Y. introduced A&W Cream Soda and A&W Diet Cream Soda through its network of franchised bottlers and distributors.
 Although cream soda had been created in 1852 by E.M. Sheldon, A&W Brands was one of the first American companies to make it commercially.
 In 1993, A&W Brands was purchased by Cadbury/Schweppes, and in 1995 Cadbury/Schweppes purchased the Dr. Pepper/Seven-Up Company, which made A&W a part of the Dr. Pepper/Seven Up, Inc.
 In 2001, DPSU purchased the Snapple Beverage Group (formally TriArc Beverages), and moved the New York-based company operations to its new headquarters in Plano, Texas.
 This acquisition put A&W within the same company as the top soda brand companies and made A&W Cream Soda the top brand in cream sodas.
Dublin Dr Pepper was the popular name for a style of Dr Pepper soft drink made by the Dublin Dr Pepper Bottling Company in Dublin, Texas.
 Dublin Dr Pepper followed the original recipe, using cane sugar as the sweetener as opposed to newer high fructose corn syrup (HFCS).
 The Dublin plant formula's use of sugar made it popular among soda fans.
 According to the corporate headquarters at Dr Pepper Snapple Group, this resulted in clashes with other bottlers and the parent company of Dr Pepper.
 On 12 January 2012, it was announced that Dublin Dr. Pepper will no longer be produced, after the Dublin Dr Pepper Bottling Company settled the trademark dispute instigated by Dr Pepper Snapple Group.
"Doctor Pepper" is a song recorded by American music producer Diplo, South Korean recording artist CL and American rappers Riff Raff and OG Maco.
 It was released on May 26, 2015 by Mad Decent.
 Produced by Diplo, "Doctor Pepper" is a trap song.
 CL later stated she wrote the lyrics after Diplo cancelled their recording session, making her write the song in a rush while drinking a can of Dr. Pepper.
Citra was a grapefruit-flavored soft drink released into the U.S. market in 1996 by The Coca-Cola Company around the same time as Surge, another citrus-flavored soft drink marketed by Coca-Cola (although Surge contained caffeine while Citra was caffeine-free).
 Citra had a very similar flavor to Fresca, especially the version of Fresca sold in Latin America, which is sweetened with sucrose (table sugar) rather than aspartame as in the American version of Fresca.
 It also had a flavor similar flavor to Squirt, except that Squirt contains a trace of orange or tangerine flavoring.
 Citra also had a very similar flavor to that of Canfield's 50/50.