The deadline for tax-return filings, a Gallup survey was released indicating that 55 percent of Americans find the tax system to be fair, the lowest percentage recorded by the organization since 2001.  The telephone poll sampled 1,005 adults from across all 50 U.S. states and the District of Columbia from April 4 to April 7, and showed that 64 percent of Americans believe their taxes will go up over the next year.

The bigger news by far was the economic data from China that was released, showing that first-quarter GDP had grown 7.7 percent on the prior year, less than the 8 percent that had been forecast by both Reuters and Dow Jones Newswire, and less that the 7.9 percent growth figure from the fourth quarter of 2012.

Additionally, industrial production was up 8.9 percent, just over a percentage point shy of the 10 percent expected gain.

The news poured fuel on gold’s downward spiral, losing over 9 percent to $1,365 per ounce, while silver lost almost 11 percent, and other commodities following suit.

The day’s bad economic news was compounded by two explosions that went off at the finish line of the Boston Marathon, three hours after the race had ended and shortly before the conclusion of trading. Initial reports had little information on the origin of the explosions, though news agencies and eye-witness accounts posted to twitter testified to a chaotic scene with many injuries and a great deal of bloodshed. Reports of multiple deaths are starting to emerge.

The Dow lost 1.79 percent on the day, closing at 14,599.20, dragged down by Caterpillar, who lost 3.19 percent with shares closing at $82.34, while oil giant Chevron (CVX) lost 2.49 percent to $116.95, and Exxon Mobil (XOM) was down 2.45 percent to $86.81.  The top three S&P losses are being seen as the direct result of the underwhelming economic news out of China.

Only one of the Dow’s components posted gains on the day, with Wal-Mart Stores (WMT) up a slight 0.22 percent to close the day at $78.73.

The S&P took a sizeable hit, losing 2.30 percent to close at 1,552.37.  The bright spot was Sprint Nextel Corp. (S) who closed up almost 14 percent to $7.09 after Dish Network (DISH) made an unexpected and significantly larger counter-offer to the SoftBank, the Japanese telecom company who had recently been bidding to purchase the U.S.’s third largest wireless service provider.

Life Technologies Corporation also clocked a large gain on the news of a merger, up 7.54 percent closing at $73.11 after it was announced that the company would be purchased by Thermo Fisher Scientific (TMO) for $13.6 billion.

Otherwise, only five other S&P components made gains on the day, while oil and gas stocks dragged the index downward, led by Pioneer Natural Resources (PXD), Newfield Exploration (NFX), Anadarko Petroleum Corp. (APC), and Nabors Industries Ltd. (NBR) all losing over 6 percent or more.

The Nasdaq took the biggest percentage loss on the day, dropping 2.38 percent to 3,216.49, weighed heavily by tech stocks.  Intel (INTC) lost 1.38 percent to close at $21.38, followed by Facebook (FB), down 3.21 percent to $26.52 , Cisco Systems (CSCO) down 2.27 percent to $21.05, and semiconductor manufacturer Micron Technology (MU), down 4.50 percent to 9.56.