I'm not sure I understand what you mean there by "as same percent of LTC", sorry.

Let me point out that Litecoin and Dogecoin still retain independent network difficulties and market prices, and therefore independent mining profitability. In particular, after the introduction of merged mining the difficulty of the Dogecoin network has started rising rapidly, and this has caused the profitability of Dogecoin to sink from about 100% of Litecoin to the ~18% where it is at the time of this writing. I expect this figure to continue to decline as more pools start doing merged mining.