You buy a $2$x S&P $500$ ETF and hold it for three days. The S&P $500$ Index returns for these three days are $6\mathrm{.}51\%,-12\mathrm{.}01\%,$ and $11\mathrm{.}19\%.$ What's the slippage of the three$-$day holding period return you experienced? That is$,$ assuming the three$-$day holding period return of the S&P $500$ Index is x$\%,$ ideally, you should have a return of $2$x$\%.$ But your three$-$day holding period return of the $2$x S&P $500$ ETF is y$\%.$ What is $($y$-2$x$)\%?$ Enter a number with two decimal points. Answer the question in percentage terms, i$.$e$.,$ if the answer is $20\%,$ enter $20\mathrm{.}00.$