Data on population indicate that:
The number of disabled people varies considerably between surveys due to different definitions. According to the Labour force surveys 15% of the population (aged 16-66) has a limiting chronic illness or disability. Other surveys tend to find that 17-20% of the population has a disability or long-standing illness, but there are examples of surveys with broad definitions counting about 25% of the population as having an impairment.
The source that is most likely to be comparable with other European countries is the EU-SILC survey.