UPDATE 1-Mexico's jobless rate 3.87 pct in September

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MEXICO CITY, Oct 19 (Reuters) - Mexico's jobless rate was a slightly lower-than-expected 3.87 percent in September, the government said on Friday, below August's 3.92 percent.

A Reuters survey of analysts had forecast an unemployment rate MXUNR=ECI of 3.90 percent for last month.

Mexico's economy grew 4.8 percent last year but is expected to expand as little as 3 percent this year as economic growth slows in the United States, its No. 1 market.

The unemployment number is considered an inaccurate picture of Mexico's jobless rate because of how it is measured. But analysts sometimes refer to it to gauge possible changes in consumer demand.