IBM:

In 2005, the company sold its personal computer business to Chinese technology company Lenovo, and in the same year it agreed to acquire Micromuse. A year later IBM launched Secure Blue, a low-cost hardware design for data encryption that can be built into a microprocessor. In 2009 it acquired software company SPSS Inc. Later in 2009, IBM's Blue Gene supercomputing program was awarded the National Medal of Technology and Innovation by U.S. President Barack Obama. In 2011, IBM gained worldwide attention for its artificial intelligence program Watson, which was exhibited on Jeopardy! where it won against game-show champions Ken Jennings and Brad Rutter. As of 2012[update], IBM had been the top annual recipient of U.S. patents for 20 consecutive years.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". In what year did IBM sell its personal computer business?
2005