Texas executes 500th inmate since 1976

(CNN) -- Kimberly McCarthy on Wednesday evening became the 500th prisoner executed in Texas since 1976, when the death penalty was reinstated in the state, according to the Texas Department of Criminal Justice.

McCarthy was put to death at 7:37 p.m. ET at the Texas State Penitentiary in Huntsville, Texas, said department spokesman John Hurt.

The 52-year-old former occupational therapist was convicted in 1997 of murdering her elderly neighbor. Authorities said McCarthy entered the retired professor's home intending to rob her; a struggle ensued, and McCarthy repeatedly stabbed her, according to the state's criminal justice website.

McCarthy then took the victim's credit cards and vehicle.

Outside the prison, nicknamed the "Walls Unit," a small crowd of demonstrators gathered Wednesday afternoon to protest the execution. They held signs that read, "Don't kill for me" and "End executions in Texas."

The Texas Court of Criminal Appeals on Monday denied McCarthy's appeal of her sentence and declined on Tuesday to reconsider it, saying her claims should have been raised previously, CNN affiliate KPRC reported.

Texas has led the nation in the number of executions since 1976, but the number of states carrying out capital punishment continues to drop.

Last year, Texas executed more people than it sentenced to death for the eighth straight year.

Four states -- Texas, Oklahoma, Mississippi and Arizona -- accounted for three quarters of all U.S. executions in 2012.