Problem 17 (2001 AMC 8)

For the game show Who Wants To Be A Millionaire?, the dollar values of each question are shown in the following table (where $K=1000$). Questions $1$ to $15$ have values: $100$, $200$, $300$, $500$, $1K$, $2K$, $4K$, $8K$, $16K$, $32K$, $64K$, $125K$, $250K$, $500K$, $1000K$. Between which two questions is the percent increase of the value the smallest?