The value of assets held in exchange-traded funds increased $85.6 billion in January, or 8.2%,  according to the Investment Company Institute.

That amounts to two-thirds of the value gained in the past year.

And was driven by interest in and appreciation of ... domestic stocks.

All told, the value of assets of the nation’s exchange-traded funds were up $129.65 billion from the end of January 2011 to the end of January 2012.

That was 12.9% from the year before, according to ICI statistics released .

The combined assets of the nation’s exchange-traded funds reached $1.134 trillion in January.

Domestic equity funds gained $47.5 billion in value in January. That was 62.1% of the $76.4 billion gain in the 12 months ending in January.

Global equity funds were virtually unchanged, falling $384 million to $272.7 billion.

Bond funds were up $10.5 billion for the month and $53.5 billion for the year.

The monthly statistical report compiles information provided to ICI by exchange-traded funds and commodity funds.

Margarida Correia writes for Bank Investment Consultant.