Historical changes of the S&P Dividend Aristocrats

Some of the best companies in the world are part of the Dividend Aristocrats list, published by S&P. Corporations that have consistently increased their dividends for at least a quarter of a century make the cut in this elite index.
Recently I stumbled upon this document (opens as a pdf file), which shows historical changes in the S&P Dividend Aristocrats list from 1989 to 2004.
You can see that in 1989, the number of companies was only 26. Only 7 of the original companies still remain in the index. The companies are: DOV, EMR, JNJ, KO, LOW, MMM and PG.
In 2004, the number of Dividend Aristocrats rose to 56. Currently there are 60 companies in the index. The percentage of companies that remain in the index after 10 years is about 30%. There have been about 116 companies that have gone through the index for the 15 year period form 1989 to 2004. So as a dividend investor, you should expect year over year changes in the index.
The average company stayed 6.5 years in the S&P Dividend Aristocrats index from the time of its addition.
Judging by the low initial number of dividend aristocrats in 1989, I think that the companies with continuous uninterrupted payment increases for periods of over a quarter of a century are a recent phenomenon, born from the ashes of the 1973- 1974 bear market. I am not sure whether dividend aristocrats have existed before 1980’s. That does mean though that this form of investing is a fad. Even if you continuously updated your dividend aristocrats’ portfolio, you would have achieved superior returns over the broad market averages .
Since the aristocrats only stay in the index for 6.5 years, shouldn’t an investor, who seeks continuous dividend raises for a maximum amount of years, invest in the dividend achievers? I do not have any historical data on the annual changes in the components on this index. Based off my limited observations over the past couple of years though, it seems to me that only 20 to 30 % of the 300+ dividend achievers out there would one day become dividend aristocrats. It also seems to me that some companies join the achievers list for a couple of years and then leave it for a while due to a difficult financial situation, only to come back several years after that.
So how will the data, presented above affect my strategy? Basically I do expect that almost all of the stocks that I buy will someday cut their dividend or freeze it for a period of time. I plan on selling companies that cut or suspend their dividend. I would not plan on selling companies that simply do not raise their dividend for a period of time, assuming that the company met my entry criteria in the first place though.
I also plan on continuously scan the market for opportunities that fit my entry criteria and allocate no more than 1% of my portfolio in a single instrument.

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