with my first pregnancy, my daughter kept going down in %. These are a few of the things I learned at the time:
1. what happens in the 3rd trimester is more important from a growth perspective than in the 2nd trimester (aka - it's too early too worry about the % at this point in time)
2. unless the % dips close to 10%, all they'll do it put you on bed rest - and you're already there
3. most important - it takes 3 % reading to plot a trend. you've only had 2, so wait until you see a 3rd to see if there is a trend.
good luck!!
Terrie