I am looking for the statistics on the ownership of intellectual
properties in government IT (information technology) acquisitions and
procurement.
Please provide links to web pages or other resources that answers the
following question:

     Are intellectual properties - especially copyright - owned by the
government or the contractor?

Pie charts showing the ratios and number of cases where
government/contractor retained the ownership of copyright to software
developed in course of government contracts is what I have in mind
primarily, but additional information such as bar graphs illustrating
the year-by-year trends would be a plus.
Federal contracts are more preferable, but state cases could suffice
if no federal data exist and the credibility and extensiveness of the
statistics are high.
If there are plenty resources available, please focus on systems
developments priced at one million dollars or more.

A few general observations under US copyright law:

A copyright in a work is owned by the author.  The author is the
person who embodies a sufficiently creative idea into a tangible
medium.  An exception arises when the person who creates the
embodiment is an employee--then, the "author" is the employer because
the work is a "work made for hire."  A "work made for hire" also
arises when one engages a person, even a person who is not an
employee, to create a work specially ordered or commissioned for use
as a contribution to a collective work, as a part of a motion picture
or other audiovisual work, as a translation, as a supplementary work,
as a compilation, as an instructional text, as a test, as answer
material for a test, or as an atlas, IF the parties expressly agree in
a written instrument
signed by them that the work shall be considered a work made for hire.
 See 17 USC Section 101.

Thus, an independent contractor, who by definition is not an employee,
will own the copyright in works he creates, UNLESS the work is the
second kind of work made for hire (one of the statutorily enumerated
classes AND a contract agreeing it is a WMFH), OR he signs a contract
assigning the copyrights in the work to the person who engaged him. 
This does not change if the "hiring" party is the government.

So, to answer your first question, "Are intellectual properties -
especially copyright - owned by the government or the contractor?,"
the answer is the contractor UNLESS it is the second kind of work made
for hire OR the contractor has signed a contract assigning the
copyrights to the government.

To answer the rest of your question, it would be necessary to examine
individual government contracts where IP was developed and see if (a)
a WMFH was contemplated and agreed to or (b) the contract contains an
assignment clause whereby the contractor assigns his IP rights to the
government.  That may be tough . . .