There was no totalization treaty with Mexico in 2001. Those 89,000 legal foreign workers in the U.S. were from countries *other* than Mexico.
The new Totalization treaty with Mexico, per Post #3 on this thread, will impact 47,000 legal Mexican's in the U.S. and 3,000 legal Americans working in Mexico, for an additional 50,000 people. That's where the 50,000 number originates.
5 Legislative Days Left Until The AWB Expires
Your post #3 is a press release which came from the SSA itself. The GAO report which analyzes the agreement describes the problems with the SSA conclusions.
In the GAO report, the SSA number of 50,000 being bandied about does not include the millions of illegal aliens already here who have become eligible under the terms of the agreement.
I quote:
"Finally, the cost of a totalization agreement with Mexico is highly uncertain. SSA’s actuarial estimate states that the cost of a Mexican agreement would be $78 million in the first year and would grow to $650 million by 2050. The estimate assumes the initial number of newly eligible Mexican beneficiaries is equivalent to the 50,000 beneficiaries living in Mexico today and would grow sixfold over time. However, this proxy figure does not directly consider the estimated millions of current and former unauthorized workers and family members from Mexico and appears small in comparison with those estimates. Although the actuarial estimate indicates that the agreement would not generate a measurable impact on the trust funds, an increase of more than 25 percent in the estimate of initial, new beneficiaries would generate a measurable impact. For prior agreements, error rates associated with estimating the expected number of new beneficiaries have frequently exceeded 25 percent. Because of the significant number of unauthorized Mexican workers in the United States, the estimated cost of the proposed totalization agreement is even more uncertain than for the prior agreements."