As we work with our customers hand-in-had in that particular regard, we're always finding new information that we then apply to Project SouthPointe to otherwise reflect what the leasing prospects are for the towers and better help us prepare the towers for those customers.
So an evergreen process, but what we've been doing is using it for the purposes of evaluating acquisitions for about the last three years.
Not to be redundant, but this question of what's changed in your thinking to buy Global Signal and thinking about Global Signal, and Jerry correct me if this is not the right number. I think over 75% of the towers in Global Signal were acquired over the last 12-18 months. So is the question about what's changed, is the thing that's changed the most maybe your expectations for what carriers are going to do over the next 12 to 36 months or are there maybe some other variables that we should think about in terms of what's changed because it just seems like if you look back over the last year, year and a half at least, the implied multiples of what was amalgamated into Global Signal were less than probably where it is today. Just trying to understand the catalyst for you today to make the buy decision versus maybe what's transpired over the last 12 to 18 months as you've considered what to do with your cash flow and your balance sheet over that period of time. Thanks.
Michael, I guess I'd say from my perspective we've asked ourselves that same question, and it's important to put everything in the proper perspective. During that time of assemblage of assets, we've spent over a billion dollars buying our own securities. So we've gotten the participation in that accretion of multiples that's occurred in the entire industry to a substantial degree.
Again, the simple answer to your question is everything is relative so it's not like we haven't participated in that expansion in multiples and valuation of this industry. We've actually benefited our shareholders quite handsomely by taking the actions we've taken.
It's also a situation of dealing with the facts that you're dealt with that you have available to you at the time. Last spring of 2005 we were all consumed, frankly as you may remember, with refinancing this company. And it made a substantial difference in the way not only our direct cost of debt, but the way the equity was valued for our company and frankly for the industry following very closely on the great work that Global pioneered as I mentioned earlier.
We were really not in a position in our view to drive the kind of shareholder returns at that time until we had ultimately accomplished what we needed to accomplish. Remember, back in the high yield days you didn't have the flexibility to buy stock, you had to buy assets. So we felt like that flexibility
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