To determine the year in which the rabbit population in South Australia was most dense, you would need to analyze the graph showing the "Boom and Bust" pattern of the rabbit population. Since I can't see the graph, I can’t provide the exact answer based on visual data.
However, if you have access to the graph, look for the highest point on the population curve, as this would indicate the year with the most dense rabbit population. Check the years you mentioned (1936, 1952, 1975, and 2000) to see which corresponds to the peak population on the graph. Based on historical data, the rabbit population was known to experience significant increases around the mid-20th century due to various factors, so the answer might likely be one of the years closest to that era, possibly 1952.
If you can provide specific details or aspects of the graph, I would be glad to help analyze it further!