I think your number is LOW, and by a lot. I am in the Liberal enclave of greater Los ANgeles area, and at least 30-40% of the Liberal Democrats I talk to are behind TRUMP 100%. the issue are simple Immigration and Trade.
I think so too... people are afraid to admit it, will only share that secretly they support Trump. It's jobs, immigration, corrupt politicians... which takes Hillary right out for the left leaning Independents. Could be a true wave election!