Less than ten percent of American who’re eligible to donate blood actually take the time to do so at least once a year. That percentage drops during the summer months according to Christine Hayes of the Des Moines based Blood Center of Iowa.

"While we see the demand for blood remain relatively stable or even sometimes increase around the July 4th holiday, unfortunately our supply tends to dip a bit simply because our donors are busy with other things," Hayes said.

Healthy adults, above the age of 16, are generally eligible to donate one pint of blood every 56 days. Hayes says regular donors have less time to give blood in the summer.

"Many of our donors are on vacation, outside enjoying the weather or attending kids’ sporting activities and it just isn’t conducive to them making an appointment to give blood," Hayes said.

The Blood Center of Iowa has launched a special promotion for fans of the Cyclones, Hawkeyes and Panthers. Hayes says the promotion involves donor centers across the state and is called "What color do you bleed?"

Blood donors can receive gifts in their favorite school colors. "So, for example, you can receive and ‘I bleed cardinal and gold’ t-shirt for your blood donation or a stocking hat or water bottle," Hayes said.

Donors can schedule an appointment online and find out more about the promotion at www.bloodcenterofiowa.org .