SAN FRANCISCO (AP) — Apple CEO Tim Cook talks about a "post-PC" era in unveiling a new iPad.Apple has popularized tablet computers with its iPads. That is hurting PC sales in the U.S. and other industrialized countries. Smartphones such as Apple's iPhones are also delaying PC replacements among consumers.Cook said Wednesday that Apple sold 172 million "post-PC" devices last year. Those are iPods, iPhones and iPads. Cook says those products now account for 76 percent of Apple sales.Cook says "Apple is at the forefront of this revolution. Apple has its feet fully planted in the post-PC future."Apple revealed a new iPad model at Wednesday's event in San Francisco. It has a sharper screen and a faster processor and goes on sale next week.