How many private housecleaners are estimated to be employed in NYC -
on and off the books? What are their average hourly wages?

I have the official statistics for on-the-books housemaids in NYC. See below.

As for off the books, anecdotal evidence is all I can find.  I tried a
union site, the AFSCME, (the American Federation of State, County and
Municipal Employees) as they are active in unionizing maids but their
statistics are drawn from the Bureau of Labor Statistics, and I've
given you direct links below.

From people with whom I am acquainted who live in NYC and Boston, the
off the book wage (as of  casual conversation over the past five
years) is:

NYC  : $50 for 3 or 4 hrs (with one paying $75 (lots of antiques))
Boston $40 for 3 or 4 hrs (with one paying $30 for 3 hrs)

P.S.  I have a robot vacuum cleaner - I do not employ a maid 
(on or off the books).

------------------------------------------
Search strategy

Go to the Bureau of Labor statistics

http://www.bls.gov/search/search.asp

(maid OR "domestic help" OR housecleaner) AND (statistics AND wages) 
AND ("new york city" OR NYC)


-----------------------------


NEW YORK-NORTHERN NEW JERSEY CPI UP 0.8 PERCENT IN February
http://www.bls.gov/ro2/oes9705.htm - 4/1/2003 7:43:03 PM GMT

http://www.bls.gov/ro2/oes9705.htm
Table 1. Employment and wage data from the Occupational Employment
Statistics survey, by occupation, New York Primary Metropolitan
Statistical Area, 2001
                                                  Mean wages |
                                                    Employment  |
Hourly | Annual(1) |  Median wages
---------------------------------------------------------------------------------------------------
Maids and housekeeping cleaners 25,640            13.66      28,420   
        13.75

The Occupational Employment Statistics (OES) survey is an annual mail
survey measuring occupational employment and wage rates for wage and
salary workers in nonfarm establishments, by industry. The OES survey
samples and contacts approximately 400,000 establishments in the
nation each year and, over 3 years, contacts approximately 1.2 million
establishments.

Lets try that Table of numbers again (so its more readable)

Maids and housekeeping cleaners 
Employment            25,640
Mean Hourly  Wage     $13.66
Annual Mean Wage      $28,420
Median Hourly Wage    $13.75

Excellent work, as usual, amalik-ga!