The Dow Jones Industrial Average soared to a record closing high, breaking through levels last seen in 2007.

Signs of a strengthening US economy, continued support from the Federal Reserve, and fairly attractive valuations compared to other assets have boosted the Dow by almost 9% so far this year.

The Dow Jones Industrial Average shot up 125.95 points, or 0.89%, to 14,253.77 at the close.

The Standard & Poor's 500 Index gained 14.59 points, or 0.96%, to 1,539.79.

The Nasdaq Composite Index climbed 42.10 points, or 1.32%, to 3,224.13.

A strong reading in the US services sector, which accounts for the bulk of economic activity, was the latest indicator of improving demand.

Gains came across the board, with 10 of the Dow's 30 component stocks reaching new 52-week highs on a day when 456 securities hit new yearly highs on the New York Stock Exchange.

The Dow Jones Transportation Average also closed at a new high after rising 1.5%.

About 71% of the NYSE stocks closed higher while 67% of Nasdaq-listed shares ended in positive territory.

About 6.41 billion shares changed hands on the New York Stock Exchange, the Nasdaq and NYSE MKT, slightly below the daily average so far this year of about 6.48 billion shares.

Outside the Dow, Google continued its gains with the stock rising 2.1% to close at $838.60, an all-time high for the internet giant.

Google is the highest-priced stock in the S&P 500.

The Dow has been in existence for more than a century.

Key dates and landmark moments for the Dow

May 1896: The Dow Jones industrial average makes its debut, consisting of the stocks of 12 companies: American Cotton Oil, American Sugar Refining Co, American Tobacco, Chicago Gas, Distilling & Cattle Feeding Co, General Electric Co, Laclede Gas Light Co, National Lead, North American Co, Tennessee Coal, Iron & Railroad Co, US Leather (preferred) and US Rubber. Of the original 12, only GE remains in the average.

April 1, 1901: US Steel Corp, a consolidation of several steelmakers and the largest company in the nation at the time, joins the Dow. It was removed May 6, 1991.

November 7, 1907: A buyout of Tennessee Coal, Iron and Railroad Co by US Steel is completed, marking the only instance in which two current constituents of the Dow combine. General Electric replaces Tennessee Coal after having been removed twice from the average.

1916: The industrial average expands to 20 stocks. It was expanded again in 1928, to 30, where it still stands.

October 1, 1928: Standard Oil Co (New Jersey), an umbrella for John D Rockefeller's oil operations, joins the Dow. Standard Oil of New Jersey became Exxon Corp in 1972 and Exxon's name changed to Exxon Mobil Corp in 1999, following an acquisition of Mobil Corp.

1928: The Dow begins being calculated with a special divisor rather than simply dividing by the number of stocks. This is to avoid distortions when constituent companies split their shares or when one stock is substituted for another. The index, though, is still called the average.

October 28-29, 1929: The Dow falls 23% over the two days in the market's most-known crash. The 12.8% fall on October 28 marks the average's second-worst daily percentage loss in its history. October 19, 1987, stands as the worst. On October 29 1929, the Dow fell another 11.7%. The days are known as Black Monday and Black Tuesday.

May 26, 1932: International Business Machines Corp joins the Dow. It was removed in 1939, but added back in 1979.

July 3, 1956: After 17 years and three months without a change in the average - the longest streak without a change - International Paper is added.

November 14, 1972: Dow posts first close above 1,000.

October 30, 1985: McDonald's Corp added to the Dow.

October 19, 1987: The Dow posts its worst daily percentage loss in its history, closing down 22.6%, or 508 points. The one-day crash, known as Black Monday, follows a bull run from a trough of 776.92 in August 1982 to a peak of 2722.22 in August of 1987.

March 29, 1999: The Dow first closes above 10,000.

November 1, 1999: Microsoft Corp and Intel Corp are added. They mark the first Nasdaq-listed stocks to join the Dow, representing the growing importance of computers and the Internet to the US economy.

September 17, 2001: The US stock market re-opens for the first time since the September 11, 2001 terrorist attacks in New York and Washington. The Dow posts its third-worst daily point loss, sinking 684.81 points, or 7.13%.

July 19, 2007: The Dow closes above 14,000 for the first time.

October 9, 2007: All-time closing high of 14,164.53.

September 29, 2008: The Dow posts its worst daily point loss, ending 777.68 points, or 6.98% lower. The move coincided with the collapse that month of Lehman Brothers and the spread of the 2008-2009 financial crisis.

October 13, 2008: The Dow registers biggest daily percentage gain of 11.08%.

June 8, 2009: General Motors, once the nation's leading car manufacturer, is removed from the Dow after it is forced to enter bankruptcy.

May 6, 2010: The Dow falls 1,010.14 points from its intraday high in a quick afternoon tumble tied to a computer-driven trading glitch - an event known as "the flash crash." The Dow recovered by day's end to close down 347.80 points, which was still its worst percentage decline since April 2009.

March 5, 2013: The Dow sets a new record high.