"comprehensive aggregate credit data in the form of bank lending in 17 advanced countries since 1870"

http://www.nakedcapitalism.com/2015/01/new-findings-point-private-credit-perfect-storm-brewing-financial-future.html

"...we live in a different financial world than any of our ancestors.

...when we observe a sharp run-up in this kind of leverage measure, financial crises have tended to become more likely; and when those crises strike, recessions tend to be worse, and even more painful in the cases where a large run-up in leverage was observed.

...Macroeconomic stability will be more elusive and that will affect all of our lives: from the risks many will face in childhood, to the security of employment at working age, to the challenge of accumulating for retirement. More financial instability will introduce more uncertainty all down the line, and that will be a very different world than the one we would have lived in only a couple of decades ago.

...We have never in human history seen a run-up in credit of the kind we have just witnessed in advanced economies since 1970, and we have never observed modern finance-capitalist systems operating over a sustained period at this kind of credit-to-GDP leverage ratio.

...The direct fiscal costs of bailouts, and the even larger indirect fiscal costs of massive recessions (unemployment, low growth, fiscal strains, etc.), have made the status quo unpalatable to governments and the taxpayers behind them.

...Alan Greenspan has noted that the idea that the financial system be left to largely run itself based on enlightened self-interest is a flawed approach.

...a potential trade-off is there, the concern that if we tighten credit too much, we might slow down growth as the price to be paid for diminishing volatility."