A home-price index considered to be the most comprehensive reading of the U.S. market posted the sharpest decline in its 17-year history, and analysts say housing has yet to bottom out.

Rapidly falling home prices in California, Florida and Nevada skewed the national results.

The Office of Federal Housing Enterprise Oversight said Thursday that home prices fell 3.1 percent in the first quarter compared with last year.

It was only the second quarter of price declines since the index started in 1991. The price index first declined on a year-over-year basis in the final quarter of 2007, when it dropped 0.45 percent.

Another widely followed reading, the Standard & Poor's/Case-Shiller index, has shown larger declines for major U.S. metropolitan areas. But analysts say the government index provides a more comprehensive reading of nationwide housing market.

That's particularly true for midwestern states, where prices never skyrocketed and have been less affected by the real estate downturn.

"Most people don't live in a Miami condo," said Michael Englund, chief economist with Action Economics in Boulder, Colo.

Still, declines in the government index, which focuses on less expensive properties and includes fewer houses bought with risky home loans that have gone sour over the past year, show the depth of the housing market's troubles.

Prices fell in 43 states, with California and Nevada showing the biggest declines. Home prices dropped by more than 8 percent in those states.

The government index also fell 1.7 percent from the fourth quarter of 2007 to the first quarter of 2008, the largest quarterly price drop on record.

"The large overhang of real estate inventory awaiting sale continues to force price declines in many areas, but particularly in places that had seen very sharp appreciation," Patrick Lawler, the agency's chief economist, said in a prepared statement. Continued...