已知单个样本选中概率，求总样本被选中比例

Question

已知一个总样本n=10，随机放回抽样，每个样本被选中的可能性为1-（1-1/n)^n, 请问整个样本中有多少比例的不重复样本？具体怎么算？这个65%怎么得来的？

For n=10, on average 65% of the examples in D will also appear in D’ as
it can be shown that the probability to choose an example is 1- (1-1/n)n