This is the best data from the disaster researchers, and it goes up and down, and it goes to the Second World War, and after that it starts to fall and it keeps falling and it's down to much less than half.
对于灾害研究人员来说 这是最理想的数字 然后上下有所浮动 然后到了二战 之后就开始一路下滑 下降至远低于一半