Can somebody tell me what happened?

Today on a Tax lien sale in NJ more than 99% of the lien were sold for 0% + premium.
The majority of the premiums were 2,3,4 and even 5 times the annual tax. Even taking into consideration the Subsequent taxes with the 18% it still doesn’t make sense to put aside that big premium! 98% to 99% of all Tax Lien are eventually paid of.
Can somebody tell me what happened over there? I sure didn’t understand.