Nick Ballard is a senior consultant at Cambashi Limited. He reports on SolidWorks sales overtaking those of CATIA:
As reported in Dassault annual reports
Year - SolidWorks - CATIA
2000 - 22,053 - 31,290
2001 - 26,183 - 33,962
2002 - 23,626 - 34,308
2003 - 25,361 - 32,163
2004 - 29,882 - 32,695
2005 - 37,280 - 34,798
The interesting thing to note is that whilst CATIA sales are very steady (V5 acceptance at lower price point than V4) those of SolidWorks have continued to grow and for the first time exceeded CATIA annual sales in 2005. Clearly there's room in the market for both.
If the day comes where CATIA is unsustainable it is not a bad position to have the market-leading package as a replacement. SolidWorks seems to have picked-up momentum to target 2D-to-3D upgraders; the market of 2D AutoCAD is large enough for 3D SolidWorks to get a decent share of, even if Inventor sells more (for the cost of an upgrade and subscription).
Since it is Autodesk's base, we should expect them to mount a solid defense of their position -- which forces down the price-points in the 2D/3D upgrade market. Competition is good: it drives vendors very hard to "go that extra mile" to get your $s!