Tampa Bay's cost of living rose slightly in the third quarter but remains second lowest in Florida and significantly below the national average, economic development officials said Thursday.The Tampa Hillsborough Economic Development Corp. said that cost-of-living estimate, based on a report from its researchers, bodes well for the economy in tandem with the continued increase in jobs and a rise in single-family housing permits.The Tampa metro area's cost-of-living index score of 92.2 is up from the second-quarter score of 89.4, but still 7.6 points lower than the national average. Among Florida metros, only the Palm Coast-Flagler County area has a lower cost of living than Hillsborough's. Similar, out-of-state metros such as Atlanta and Raleigh and Charlotte, N.C., all came in higher.The EDC's index, which does not measure inflation, looks at relative price levels for six categories of consumer goods and services: grocery items, housing, utilities, transportation, health care and miscellaneous.In some cases, there was a wide disparity among the categories that were measured. Tampa and Raleigh, for instance, were far afield when it came to the cost of buying groceries and paying the electric bill. Tampa Bay's grocery index came in at 94.6, while Raleigh's was well over the national average at 113.8.Note: The utilities score was based on data from TECO Energy. An earlier version of this story indicated it included Duke Energy customers elsewhere in Tampa Bay.