ASSET VALUE SHRINKING

Can someone explain how I'm losing trillions of dollars in asset value, mostly from the devaluation of government assets, but at the same time my monthly governmental expense is steady or growing? I've lost about 7 trillion in value across my countries and enterprises over the last 18 months, for apparently no reason at all????

White Giant...Country names: Martinia, Grand Martin, and others

Government assets depend on the market value of the 'goods' associated with the government.
If for example; hospitals, schools, etc. drop in market value your gov asset value will also shrink.

Has there been a notable drop in governmental asset values over the last 18-24 game months?

Yes there has been. You can take a look at the market value graphs of the relevant products.