Devoted to Managers and those that seek to improve their management skills

For the tenth month in a row, home prices in the U.S. dropped, with data for October showing the largest drop since 1991, according to Standard & Poor's/Case-Shiller home price index. It's also the 23rd month in a row where growth either slowed or declined.

The Case-Shiller index tracks the prices of single-family homes in 10 key metropolitan areas. It's considered an accurate measurement device because it follows actual properties and their rise and fall in price, rather than using the median price of a group of homes sold over a month.

This year the index fell by 6.7 percent, an all-time high, with the 6.3 percent drop in April 1991 being the former low.

Case-Shiller also has a broader index which measures 20 metropolitan areas, where 11 of the 20 had record drops in single-family home prices, with all 20 declining in price from the month before.

The worst performer in the broader index was Miami, dropping by 12.4 percent, with Tampa not too far behind with a 11.8 decline.

Also dropping in the double digits were Las Vegas, Phoenix, San Diego and Detroit. Only three of the 20 areas experienced a gain year-over-year, with Seattle, Portland, Ore. and Charlotte falling in that category. Charlotte let all of them with a 4.3 percent gain in single-family housing prices from last year in October.

"No matter how you look at these data, it is obvious that the current state of the single-family housing market remains grim," said Robert Shiller, co-creator of the index.