Question: What year was the California theme park, which features the steel Kong roller coaster, opened?

Context paragraphs:
Griffon (roller coaster): Griffon is a steel Dive Coaster roller coaster located at the Busch Gardens Williamsburg amusement park in James City County, Virginia, United States.  Designed by Bolliger & Mabillard, it is 205 ft high, and is the second-fastest (71 mph ) Dive Coaster built.  The roller coaster features two Immelmann loops, a splashdown, two vertical drops and was the first of its kind to use floorless trains.  Griffon was announced to the public on August 23, 2006 and opened on May 18, 2007 to positive reviews by both newspapers and enthusiasts.  In 2007, "Amusement Today"' s annual Golden Ticket Awards voted it the third-best new steel roller coaster of that year and the 27th-best steel roller coaster.  It was voted the 33rd-best steel roller coaster in 2013.

Six Flags Discovery Kingdom: Six Flags Discovery Kingdom (formerly known as Six Flags Marine World, Marine World, The New Marine World Theme Park, and Marine World Africa USA) is a 135-acre (55 ha) animal theme park located in Vallejo, California, roughly halfway between San Francisco and Sacramento on Interstate 80.  The park includes a variety of roller coasters and other amusement rides. Discovery Kingdom has been part of the Six Flags chain of amusement parks since 1999.

Tatsu: Tatsu is a steel flying roller coaster designed by Bolliger & Mabillard at the Six Flags Magic Mountain amusement park located in Valencia, California, United States.  Announced on November 17, 2005, the roller coaster opened to the public on May 13, 2006 as the park's seventeenth roller coaster.  Tatsu reaches a height of 170 ft and speeds up to 62 mph .  The ride's name means "Flying Beast" in Japanese.  The roller coaster is also the world's tallest and fastest flying coaster; is the only flying roller coaster to feature a zero-gravity roll; and has the world's highest pretzel loop.  It was the world's longest flying coaster until The Flying Dinosaur surpassed it.

Intimidator (roller coaster): Intimidator is a steel roller coaster built by Bolliger & Mabillard at Carowinds.  The roller coaster is located in the Celebration Plaza section of the park on the former site of the Wild Thornberry's River Adventure log flume ride.  Intimidator is the thirteenth roller coaster installed at Carowinds and is located near the entrance of the theme park.  It is currently one of the tallest, fastest and longest roller coasters in the Southeast with a 232 ft lift hill, a top speed of 75 mph and a track length of 5316 ft .  It was announced on August 26, 2009 and opened March 27, 2010.  The roller coaster's name comes from the nickname of NASCAR driver Dale Earnhardt.

Fujiyama (roller coaster): Fujiyama is a steel roller coaster at Fuji-Q Highland, Fujiyoshida, Yamanashi, Japan.  When Fujiyama opened in 1996 it was the world's tallest roller coaster at 259 ft , and had the largest drop in the world at 230 ft .  Fujiyama was also the world's fastest roller coaster for a year of its operation, succeeded by Tower of Terror at Dreamworld theme park in Queensland, Australia in 1997.  Despite being the world's fastest roller coaster in operation for a year, Fujiyama set no world records for roller coaster speed.  Steel Phantom at Kennywood set the world record for speed before engineers added additional brakes to slow the ride down because of safety and rider comfort concerns.

Goliath (Six Flags Over Georgia): Goliath is a steel Hyper Coaster located at the Six Flags Over Georgia amusement park in Cobb County, Georgia, United States.  Designed by Bolliger & Mabillard it reaches a maximum height of 200 ft , a top speed of 70 mi/h , and has approximately 4480 ft of track.  Great Gasp and Looping Starship were both removed by the end of the 2005 season to make room for the roller coaster.  Goliath was announced to the public on September 1, 2005 and opened on April 1, 2006.  In 2006, "Amusement Today"' s annual Golden Ticket Awards voted it the fourth-best new steel roller coaster of that year and the 9th-best steel roller coaster.  It was voted the 7th-best steel roller coaster in 2013.

Millennium Force: Millennium Force is a steel roller coaster built by Intamin at Cedar Point amusement park in Sandusky, Ohio, United States.  It was the fourteenth roller coaster to be built at the park since Blue Streak opened in 1964.  Upon completion in 2000, Millennium Force broke six world records and was the world's first Giga Coaster, a roller coaster that exceeds 300 ft in height and completes a full circuit.  It was briefly the tallest and fastest in the world until Steel Dragon 2000 opened later the same year.  The ride is also the third-longest roller coaster in North America after The Beast at Kings Island and Fury 325 at Carowinds.  It was the first roller coaster to use a cable lift system rather than a traditional chain lift.  The coaster has a 310 ft , 45-degree lift hill with a 300 ft drop and features two tunnels, three overbanked turns, and four hills.  It has a top speed of 93 mph .

Kong (roller coaster): Kong is a steel Suspended Looping Coaster, made by Vekoma, located at Six Flags Discovery Kingdom in Vallejo, California.

White Cyclone: White Cyclone (ホワイトサイクロン , Howaito Saikuron ) is a wooden roller coaster at Nagashima Spa Land in Mie Prefecture, Japan.  At 1700 m in length, White Cyclone is the third longest wooden roller coaster in the world, and is the longest wooden roller coaster outside of the United States.  Despite its length, White Cyclone is still considerably shorter than the 2479 m Steel Dragon 2000, the world's longest steel roller coaster, which is also at Nagashima Spa Land.  In addition to being the third longest wooden roller coaster, White Cyclone is the seventh tallest wooden roller coaster in the world and the fourth tallest wooden roller coaster outside the United States.  A single ride on the White Cyclone costs ¥1,000 (approximately $9 USD), and the ride is restricted to those individuals above 1.3 m in height; and those individuals under 54 years of age.

Wooden roller coaster: A wooden roller coaster is most often classified as a roller coaster with running rails made of flattened steel strips mounted on laminated wooden track.  Occasionally, the support structure may be made out of a steel lattice or truss, but the ride remains classified as a wooden roller coaster due to the track design.  Because of the limits of wood, wooden roller coasters, in general, do not have inversions (when the coaster goes upside down), steep drops, or extremely banked turns (overbanked turns).  However, there are exceptions; the defunct Son of Beast at Kings Island had a 214 ft drop and originally had a 90 ft loop until the end of the 2006 season, although the loop had steel supports.  Other special cases are Hades 360 at Mount Olympus Water and Theme Park in Wisconsin Dells, Wisconsin.  The coaster features a double-track tunnel, a corkscrew, and a 90-degree banked turn.  There is also The Voyage at Holiday World (an example of a wooden roller coaster with a steel structure for supports) featuring three separate 90-degree banked turns.  Ravine Flyer II at Waldameer Park has a 90-degree banked turn, T Express at Everland in South Korea with a 77-degree drop, and Outlaw Run at Silver Dollar City which has 3 inversions and 120-degree overbanked turn.

Supporting paragraphs: Kong (roller coaster) Six Flags Discovery Kingdom
Answer: 1999