Very few people are exempt these days. The list includes serving Police Officers, who get a further 5 year exemption when they leave or retire, Solicitors/Barristers/Judges (who also get the 5 year exemption), members of the armed forces, The insane and anyone who has an unspent conviction within the last 10 years and the over 70's. The law was changed in 2004 and brought in occupations previously exempt, for example Doctors, Vets, Pharmacists, MP's, Peers, Dentists,etc.
One of my fathers friends was on the Moors Murders trial in 1966, he was excused from any further Jury service for life.
Pete