给定一篇文章，请对其中的单词进行词频统计并输出出现频率最高的10个单词及其出现的次数。
The quick brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy dog again and again.
quick: 2
brown: 2
fox: 2
jumps: 2
over: 2
the: 4
lazy: 2
dog: 2
again: 2
and: 1