Quarterly financial data (unaudited)

12 Months Ended

Dec. 31, 2011

Quarterly financial data (unaudited)

13. Quarterly financial data (unaudited)

Summarized quarterly financial information for 2011 and 2010 is as follows:



		First Quarter		Second Quarter		Third Quarter		Fourth Quarter

		(dollars in thousands)
2011
Operating revenues	$	269,774	$	379,803	$	432,530	$	308,171
Operating margin		65,935		63,702		64,884		43,299
Net margin		16,110		12,718		10,408		(1,499	)
2010
Operating revenues	$	304,072	$	326,110	$	371,398	$	292,565
Operating margin		65,895		59,769		63,914		49,671
Net margin		14,604		7,400		13,848		(2,119	)

Our business is influenced by seasonal weather conditions. The negative net margins in the fourth quarter of 2011 and 2010 were due to reductions to revenue requirements in order to achieve the targeted margins for interest ratio of 1.14.

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References+ Details