The Chicago Fed National Activity Index (CFNAI) decreased from 0.54 points in December 2011 to 0.22 points this January, although the index's three-month moving average still posted a year-long high, according to data released Tuesday by the Federal Reserve Bank of Chicago.

Despite the month-to-month decrease of 0.32 points, the January CFNAI -- a weighted average of 85 national economic indicators taken across the four concentrations of production, employment, personal consumption and sales -- still remained positive and saw its second consecutive month of above average values.

Furthermore, the CFNAI three-month moving average increased from 0.06 points in December to 0.14 in January, making it the highest three-month moving average value since March 2011.

Following last March, the CFNAI had seen only negative monthly index numbers for nearly the entirety of 2011, a slump finally broken by last month's reported 0.54 points in December.

According to the Chicago Fed, any index value above zero signifies the national economy is expanding at an above average historical trend rate of growth, while a negative number signifies below-average growth.

January's CFNAI thus indicates that the US economy is currently growing at a rate better than historical average, though still below the 0.7-point mark that, if long-term, would indicate concerns of increasing inflation.

Bolstering the January index most were higher figures for the CFNAI's employment category, which lent an increase of 0.35 points to the index and were up from the December employment figure of 0.28 points. The index corresponded to the January data from the US Department of Labor that the US unemployment rate declined to 8.3 percent from December.

In contrast, negative values in the January index for the housing and consumption category brought the CFNAI down slightly, with the housing and consumption posting of -0.27 points, the only negative value in the CFNAI's four economic categories.

While improvement in the US housing market may be critical for continuing US economic growth in the future, the January CFNAI was still a striking improvement from the index's low of -4.0 that occurred only three years ago, in 2009.