That article is not entirely true.  Dogecoin is merged mined using AuxPOW for Scrypt, which means most of the hash rate mining Litecoin is also used for Dogecoin, hence it is Litecoin that has the hashing power security.

As of now:

Litecoin Hashrate: 300.50 TH/s
Dogecoin Hashrate: 208.83 TH/s

So about 66%.