How big, in terms of revenues per year, is the "data modeling tools"
market in past years, and what will it grow to in the years to come?

See http://searchdatabase.techtarget.com/sDefinition/0,,sid13_gci211902,00.html
and also http://www.4guysfromrolla.com/webtech/030399-1.shtml for good
descriptions of data modeling.

Many companies large and small use data modeling tools, to help them
to design databases effectively (using database management system
software from companies like Oracle, Microsoft, IBM, Sybase and
others), based on different business rules.  The data modeling tools
market is defined by several players, such as Computer Associates,
Sybase, Embarcadero, Popkin and many others, although according to
market share figures from the year 2000, these companies are the
market leaders in terms of market share, with Computer Associates,
Sybase and Embarcadero taking up 81% of the market altogether.  

Here are the url's for the companies above, referencing their data
modeling products:

Computer Associates:  http://www3.ca.com/Solutions/Product.asp?ID=260
Sybase:  http://www.sybase.com/products/designtools/powerdesigner
Embarcadero:  http://www.embarcadero.com/products/erstudio/index.asp
Popkin:  http://www.popkin.com/products/product_overview.htm

See
http://www.quest.com/industry_coverage/data_modeling_tools_and_trends.asp
for an excellent report by Carl Zetie of GIGA Information Group,
entitled "Market Overview:  Data Modeling Tools and Trends, 2001
Update" for more information.

I need to know how big the data modeling tools market is, in terms of
worldwide sales revenues, for the last two years (2000 and 2001), and
need also to know what the expected growth is for this market over the
next two years (2002 and 2003).