在以下英文文本中找到所有的人名，并按照出现次数从高到低排序。
"John Smith is a software engineer at Google. Mary Johnson is a marketing manager at Facebook. David Lee is a data scientist at Amazon. John Johnson is an operations manager at Uber."
John Smith, Mary Johnson, David Lee, John Johnson。排序：John Johnson(2次), John Smith, David Lee, Mary Johnson。