What is the average monthly return of the SPX?

Can you please provide me with some insight into the average monthly return of the S&P 500 Index, also known as the SPX? I'm interested in understanding how this benchmark for the U.S. stock market has performed on a monthly basis over time. Additionally, is there any pattern or trend that has emerged in terms of its monthly returns? Your expertise in the field of finance and cryptocurrency would be invaluable in helping me gain a clearer understanding of this topic.