By Carey Gillam

(Reuters) - Cooler temperatures and mild weather continued to help loosen the grip of a historic drought in Texas, but more than 90 percent of the southern state still suffered from extreme conditions, according to a national drought report issued Thursday.

The report stated that 91.87 percent of the Lone Star State was considered in extreme or exceptional drought. That was down from 91.96 percent a week earlier.

And the worst level of drought, exceptional drought, fell to 72.61 percent from 73.13 percent of the state, according to the Drought Monitor, which is compiled by a team of federal and academic scientists.

Still, Texas continued to suffer the effects of a year with virtually little to no rainfall. Texas so far has suffered more than $5 billion in agricultural losses, and wildfires have scorched millions of acres during the state's longest dry period on record.

And on top of that, earlier this week, a mammoth dust storm enveloped Lubbock, Texas, as it swept across the state.

Oklahoma saw an improvement in the level of exceptional drought, which dropped to 59.09 from 59.10 percent of the state. But taking into account the second-worst level of drought, extreme drought, the dryness spread to 87.85 percent of the state from 80.31 percent.

Louisiana saw drought areas expand, with more than 40 percent of that state now in extreme or exceptional drought, up from 36 percent a week ago, the report said.

And drought in the key wheat-producing state of Kansas grew worse, expanding to 32.50 percent of the state in extreme or exceptional drought, up from 26 percent a week earlier.

(Reporting by Carey Gillam in Kansas City; Editing by John Picinich)