Once a year. What a joke.
If it's to be considered part of the communion service, it ought to be done every time communion is served.
But then the masses would be over 45 minutes and people would get really edgy at that.
Most can't even force themselves to arrive and leave on time, much less agree to stay LONGER.
Who ever said it was or is supposed to be considered as part of the "Communion service" (Properly named the Liturgy of the Eucharist or the Communion Rite).
As for frequency, the faithful are obligated to receive Communion once within their lifetime and at least on an annual basis thereafter. (kinda like that good old fashioned foot washing).
Peace be with you.