From 1869 to 1918, the per-capita GDP increases from $4600 to $12000 -- a time constant of 1.95% per year. From 1918 to 2011, the per-capita GDP increases from $12000 to $47300 -- a time constant of 1.47% per year. That is, the pre-Fed period experienced 32% faster growth over-all, or at least that's what it looks like, to me. Feel free to contest my analysis.

http://www.wolframalpha.com/input/?i=log%2812000+%2F+4600%29... -- first time period. Per-capita GDP starts at $4600 and ends at $12000 over 49 years.

http://www.wolframalpha.com/input/?i=log%2847300+%2F+12000%2... -- second time period. Per-capita GDP starts at $12000 and end at $47300 over 93 years.