Overall charitable revenue grew 6.8 percent for the three months ending August 2011, compared to the same period in 2010. Online giving is on the up swing as well, increasing 6.1 percent for the same period of time.

These are the results of the newest research in The Blackbaud Index, by software firm Blackbaud in Charleston, S.C. Updated quarterly, the Index reports overall charitable revenue from 1,276 nonprofit organizations and online giving from 1,780 organizations chosen by Blackbaud. This installment reported revenues from May-August 2011.

Chuck Longfield, chief scientist and creator of The Blackbaud Index, noted that even though nonprofits saw growth this past summer, unlike 2010, giving slowed when August arrived.

“Not surprisingly, it appears that our country’s continuing economic problems are once again weigh on donors’ checkbooks,” said Longfield. “Our data illustrates the challenges most nonprofits are likely facing as they try to achieve sustainable, consistent growth.”

Small organizations (organizations with revenues less than $1 million the previous year) had the greatest increase in revenue, with a 19.3 percent for August, compared to 10.3 percent in August 2010.

Organizations with revenue between $1 million and $10 million saw charitable revenue decrease by 0.3 percent. In August 2010, charitable revenue increased by 1.3 percent. In 2011, prior to August, charitable revenue increased by 14.1 percent and 8.5 percent respectively in June and July.

Larger organizations also had significant increase this summer. Organizations with revenues larger than $10 million saw a 6.4 percent increase this past August compared to only 4.5 percent in August 2010.

In terms online giving, revenue increased 6.1 for the three months ending August 2011. Online giving was extrapolated out to generating $426 million during a 12-month period based on data collected from 1,780 organizations.

Overall, even though organizations saw a positive 6.1 percent increase in August, it is a far cry from the 17.2 percent increase seen August of 2010.

For small organizations the differences was even more disparate. In August 2011, online revenue saw a -0.6 percent decrease compared to the 30.7 percent increase in August 2010.

Medium organizations also saw a decrease in online revenue this August. They witness a -3.3 percent decrease in online revenue, when at the same point last year; they had a 13.3 percent increase in online revenue.

Large organizations were the only ones to see an increase and only by a small margin. In August 2011, large organizations saw a 17 percent increase in charitable giving as opposed to August 2010, with a 16.2 percent increase.

The following is a breakdown by organization type for how each fared in terms of charitable giving and online giving for the three months ending August 2011.

* Healthcare- charitable revenue decrease of 5.5 percent, online revenue increase of 3.1 percent.

* International affairs- charitable revenue increase of 26.4 percent, online revenue increase of 33.7 percent.

* Environmental and animal welfare- charitable revenue increase of 1.7 percent, online revenue increase of 20.6 percent.

* Arts, culture and humanities- charitable revenue increase of 11 percent, online revenue decrease of 5.7 percent.