I don't think there's anything built in, so you'd probably have to iterate through the entire collection and keep a count yourself.
"On one of my cards it said I had to find temperatures lower than -8. The numbers I uncovered were -6 and -7 so I thought I had won, and so did the woman in the shop. But when she scanned the card the machine said I hadn't. "I phoned Camelot and they fobbed me off with some story that -6 is higher - not lower - than -8 but I'm not having it." -Tina Farrell, a 23 year old thicky from Levenshulme, Manchester.