Change over time in the age and number of children registered for autism-specific funding was examined, prior to and following introduction of the revised diagnostic criteria (the Diagnostic and Statistical Manual of Mental Disorders—fifth edition; DSM-5). De-identified data for 32,199 children aged under 7 years between 2010 and 2015 was utilised. Fluctuations were evident in the frequency and age of diagnoses, with slight increases in age of diagnosis corresponding with increases in frequency of diagnoses. The incidence of autism increased from 2010 to 2013, and then plateaued to 2015. A significant trend-relative reduction in the number of children registered to receive autism-specific funding was evident post 2013, suggesting the more stringent DSM-5 criteria may have curbed the trend of increasing diagnoses over time.