From a statistical perspective, the historical closing high set by the S&P 500 index last night is quite commemorative for the index - it is the 1200th time since 1957 that the S&P 500 index has set a closing high record, and also the 16th time this index has rewritten its history. So far this year, more than one-third (35%) of the trading days of the S&P 500 index have closed at a historic high, a proportion that has only appeared three times in the history of the same period in previous years.