The Office of the High Commissioner for Human Rights (OHCHR) just published a report on the Realization of the Right to Work, which has a full chapter on the right to work of persons with disabilities.
The report mentions that although a high percentage of people with disabilities are able to work, their employment rate is much lower than that of the general population. Furthermore persons with disabilities in employment are frequently subject to less favourable conditions of pay, precarious work regimes and poor career prospects.
More information is available in http://ap.ohchr.org/documents/dpage_e.aspx?si=A/HRC/31/32
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