Between 1 and 4% of the populations of developed nations are diagnosed with learning disability. In Australia, an estimated 1.9% of the population exhibit learning disability either as a primary disability or as a secondary condition, and approximately half of these people require continuing support in daily living, including mobility, self-care, and socialization. After improvements in basic public health measures, life expectancy in most developed nations increased over the course of the 20th century, and this trend included people with learning disability. Thus, by the end of that century, the survival estimates for people with mild learning disability living in developed countries was 70 years, and nearly 60 years of age for those with severe learning disability.