DETROIT (Reuters) - Automakers reported their strongest U.S. October sales in years on Monday, but top-seller General Motors Co (>> General Motors Company) missed expectations.

Monthly U.S. sales of the six largest automakers as measured in U.S. market share rose 6 percent from a year ago, matching analysts' expectations.

Declining gasoline prices helped boost demand for SUVs and crossovers. Ford Motor Co (>> Ford Motor Company) said utility vehicles and trucks accounted for 72 percent of its sales, up from 68.5 percent a year ago.

Fiat Chrysler Automobiles'  (>> FIAT SPA) U.S. October sales rose 22 percent on strong pickup truck and Jeep SUV demand, beating analysts' expectations.

While Ford sales fell 2 percent to 188,654 vehicles, the result beat analysts' expectations by nearly 6,000 vehicles, according to a Reuters poll.

The lower monthly sales by Ford were expected because the company has lowered production of the F-150 pickup in recent months during the transition to an aluminum-bodied model, which goes on sale later this year.

A poll by Thomson Reuters of 29 economists forecast a seasonally adjusted annualized sales rate of 16.5 million vehicles. RBC Capital Markets at midday said October sales will be about 16.4 million on an annualized basis.

Each month, auto sales are an early snapshot of U.S. consumer spending.

“The U.S. economy has steadily improved all year and now we are poised for a stronger expansion backed by an improved job market, higher consumer confidence and lower fuel prices,” said Kurt McNeil, GM's U.S. sales chief.

GM's is well-laden with truck inventory which bodes well in the lucrative pickup truck market in the last quarter, when truck sales traditionally rise, said John Krafcik, president of TrueCar.

And GM's average selling price for its vehicles related to incentives that cut costs to consumers is the highest among the three major domestic automakers, which will help the company's bottom line, Krafcik said.

Toyota Motor Corp (>> Toyota Motor Corp) sales rose 7 percent to 180,580, matching analysts' expectations.

Nissan Motor Co (>> Nissan Motor Co Ltd) and Honda Motor Co (>> Honda Motor Co Ltd) each reported robust sales of crossover models and record October U.S. sales for their core brands. Nissan beat analysts' expectations but Honda missed estimates.

GM sales were 0.2 percent above results from October 2013, at 226,819 vehicles, but missed estimates of analysts by more than 5,000 vehicles. GM said it is taking steps to boost profit at the cost of total sales by lowering fleet sales of large SUVs.

Chrysler's Ram pickup truck sales rose 33 percent. Sales of GM's pickup trucks, including the Chevrolet Silverado and the GMC Sierra, gained 16 percent, to 68,530.

Ford's F-Series sales slipped 0.6 percent in October to 63,410. It was a rare beat by GM's pickup trucks over Ford's F-Series.

Chrysler's sales of 170,480 beat expectations by about 4,000 vehicles.

(Editing by Lisa Von Ahn, Jeffrey Benkoe and Matthew Lewis)

By Bernie Woodall and Ben Klayman