Question: At what time did a series of improvements take place at the Music Concourse?
About the article "Golden Gate Park", section "Music Concourse Area".

Candidate passages:
A concourse is a place where pathways or roads meet.
Concourse may also refer to:  Concourse House, in Liverpool  Concourse Plaza Hotel, in the Bronx  Concourse Program at MIT  Concourse at Landmark Center, in Atlanta  Concourse on High, Bahá'í concept  IND Concourse Line  Music Concourse, in San Francisco  The Concourse, Chatswood  The Concourse, in Singapore  Winter Street Concourse, in Boston  
Major features.
Music Concourse Area.
The Music Concourse is a sunken, oval-shaped open-air plaza originally excavated for the California Midwinter International Exposition of 1894.
Its focal point is the Spreckels Temple of Music, also called the "Bandshell," where numerous music performances have been staged.
It includes a number of statues of various historic figures, four fountains, and a regular grid array of heavily pollarded trees.
Since 2003, the Music Concourse has undergone a series of improvements to include an underground 800-car parking garage and pedestrianization of the plaza itself.
It is surrounded by various cultural attractions, including:
At the time of its closure, Concourse C had 3 gates: C5, C7, C9Concourse C opened as Concourse 6 in 1959, serving Eastern Air Lines.
During the mid-1960s, Concourse C received an extension of its second floor and was equipped with air conditioning.
Since then, it did not receive any major interior modifications or renovations.
Following the renumbering of gates and concourses in the 1970s, Concourse C had Gates C1 to C10.
The opening of an international arrivals hall in Concourse B during the 1980s saw Gate C1 receive the ability to process international arrivals.
Following the demise of Eastern Air Lines in 1991 the concourse was used by a variety of African and Latin American carriers.
Many of these airlines' flights would arrive at Concourse B and then be towed to Concourse C for departure.
By the end of the decade, the construction of American Airlines' baggage sorting facility between Concourses C and D saw the closure of all gates on the west side of the concourse, with Gate C1 following soon afterward.
From the 2000s (decade) on, the concourse consisted of just four domestic-only gates, each of which were capable of accommodating small-to-medium jet aircraft from the Boeing 737 up to the Airbus A300, and had American Airlines as its sole tenant.
As part of the North Terminal Development project, Concourse C closed on September 1, 2009, and was demolished.
The demolition of Concourse C allowed for the construction of new gates where the concourse stood. 
It was announced in September 2011 that all five of Liverpool's underground stations had secured £40 million investment from Network Rail to allow improvement works to take place, with half that amount earmarked for Central Station refurbishment.
The entire station closed on 23 April 2012 to allow necessary improvement works to take place, primarily to the platform area of the station, although the concourse will also see minor improvements.
Some of the improvements at Central Station include an additional lift, new escalators and refreshed wall cladding, among others.
The single Wirral Line platform at Liverpool Central reopened on 25 August 2012, and the Northern Line platforms (1+2) reopened on 22 October 2012. 
A $70 million renovation of airport facilities, designed by Brubaker, Brandt Inc., was initiated in 1979 for the airport's 50th anniversary and completed in 1981.
This upgraded the airport's capacity to 250 flights per day by adding what is known today as Concourse B and added fully enclosed jetways at every gate.
Ten years later in 1989, a second, $15.5 million, seven-gate south concourse (now Concourse A) was dedicated.
The concourse was used exclusively by US Airways at the time, and later housed hubs for both America West Airlines until 2003, and Skybus Airlines until they shut it down in 2008 due to their bankruptcy.
A north concourse was completed in 1996, which is now Concourse C, and was expanded in 2002.
Between 1998 and 2000, numerous airport expansion and renovation projects were completed, including a $25 million terminal renovation in 1998 that included additional retail shops, new flight information displays, enhanced lighting, upgraded flooring, and a new food court.
Also, new hangars and office spaces were completed for NetJets in 1999, as well as a $92 million parking garage including an underground terminal entrance, new rental car facilities, dedicated ground transportation area, improved eight-lane terminal access on two levels, and a new atrium and entrances in 2000, which were designed by URS Corporation.
On April 25, 2004, a new control tower directed its first aircraft, ushering in the beginning of several major facility enhancements to be constructed through 2025.
On October 21, 2010, a new arrivals/departures board was installed in the place of the old one in the main entrance areaPort Columbus is currently going under a Terminal Modernization Program, which includes new terrazzo flooring throughout the airport, new restrooms, and new LED lighting.
Construction started on Concourse A in late 2012 and is expected to be complete throughout the concourse in 2015.
In 2013, the airport completed a US$140 million runway improvement.
The south runway was moved farther from the north runway, creating a buffer distance which would enable simultaneous takeoffs and landing on both the north and south runways, and increase the volume of air traffic.
Columbus mayor Michael B. Coleman commented, "as the city grows, the airport needs to grow with it."