My email is currently about half it was earlier in the year. (My server was offline for a few days and that has magically taken it off the crap email list somehow
)
Currently according to my daily spamfilter stats I'm receiving ~450 smtp connections/day, ~300 denied bad domain, ~60 queued for delivery, ~45 rejected and the rest spam tagged.
I use fail2ban and geoip/ban country.
I also run banip and adblock on my gateway firewall that may or may not be helping. Nor to I make use of any spam learning functions available on the sme server.
I don't have any stats for a direct internet facing sme server to compare results with.