Semico Research recently published a detailed forecast and analysis of the analog market. But the headline numbers are publicly available. The analog market totaled $40B in revenue in 2012 and is expected to grow by 9.5% in dollar value and 6.4% in unit growth into 2013. That is a healthy chunk of the whole semiconductor market, especially since it excludes all the mixed-signal SoCs which are primarily digital chips that contain some on-chip analog IP.
This seems to be driven by two main factors. One is clearly the growth in mobile. Every mobile electronic system such as a smartphone (or even a feature phone aka dumbphone) contains power management chips. Secondly, the real world is analog and so any device that has to interface to the real world requires analog interfaces. As the electronic content of everything increases, but most especially the large consumer marketplaces such as automobiles and homes, the need for analog interfaces also increases. As the Internet of Things (IoT) starts to become a reality with connectivity everywhere always then this will continue to increase demand for analog interfaces of all kinds.
If you are interested in the full report then contact Rick Vogelei at Semico Research, email@example.com.