In light of the Animal rights campaign group disrupting the Grand national last weekend I thought it timely to repost the graph below with updated data (1970 to 2023).
Over time, fewer horses are falling in the race and the number of horses being pulled up is trending upwards.
There is an upward trend in the number of 'unseated riders' over the period. This is when only a jockey hits the turf. What appears to be happening is that risks/costs imposed on the horse have been lowered over time.