As the Histadrut labor federation goes on strike on Monday in the name of subcontracted workers, the question comes up: Just how many of these workers are there?

The short answer is that no one knows. Estimates place the figure at 5% to 10% of the workforce, or 150,000 to 300,000 people. The government, the country's largest employer, employs many of these people. Yet it never looked into just how many, apparently.

Hundreds more work at each of the bodies threatening to strike on Monday - Bank Discount employs 500, the Ashdod port employs 250, and the local authorities each have a few hundred, for example.

Mind you, these figures include outsourced workers in all fields, including computing and high tech. People in the latter group generally aren't considered disadvantaged - they earn well and receive proper social benefits.

The real issue involves those employed in cleaning and security, who make up some of this country's poorest workers. Cautious estimates state that there are about 150,000 of them, half of all subcontracted workers.

However, the state's expenditures on subcontracted employees are in line with international averages, it found based on OECD statistics. The most recent OECD report, from 2009, compared governments' expenditures on subcontractors to GDP. The average was 10%.

Israel's government spent 13% of the GDP on subcontractors. While this is about 30% more than the average in developed countries, that figure is increasing. Plus, Israel's figures are similar to those of many European nations, and there are nine developed nations that spend between 12% and 14% of GDP on outsourcing.

However, the numbers do not necessarily reflect cultural differences. In Sweden, for instance, subcontracted workers are subject to collective labor agreements.

The OECD encourages outsourcing, which it says increases the efficiency and quality of government services.