I think they're slightly down on last year overall. London are definitely the outliers but Wakefield have seen a big drop this year as well, partly because their stadium has had its capacity slashed after it was refused a safety certificate.
Not quite down - they are (well were, I'm yet to see the figures for over Easter) about 2% up - most are expected. Salford have seen a big rise, st.helens and (perhaps slightly surprising) hull Kr are the big winners so far. No prizes for the big losers thus far.
The last set of complete statistics I have (from an English rl forum) are below (though they're a few rounds ago now)
Club... Games... 2014... 2013... %gain/loss
Salford... 5... 30606... 14601... +109.62%
St Helens... 5... 68355... 59620... +14.65%
Hull KR... 5... 42736... 37677... +13.43%
Castleford... 5... 36815... 33288... +10.60%
Leeds... 5... 71446... 71641... -0.27%
Widnes... 5... 29482... 29788... -1.03%
Wigan... 6... 78169... 80918... -3.40%
Warrington... 5... 54261... 57026... -4.85%
Hull... 6... 60645... 65173... -6.95%
Huddersfield... 4... 28494... 30739... -7.30%
Bradford... 5... 36655... 42739... -14.24%
Catalans... 4... 32351... 40229... -19.58%
Wakefield... 4... 18435... 28598... -35.54%
London... 5... 5678... 9953... -42.95%
********************************************
Current Average Attendances V Same Fixtures Last Year
Club... SL:2014... (SL:2013)
Leeds... 14289... (14328)
St Helens... 13671... (11924)
Wigan... 13028... (13486)
Warrington... 10852... (11405)
Hull... 10108... (10862)
Hull KR... 8547... (7535)
Catalans... 8088... (10057)
Castleford... 7363... (6658)
Bradford... 7331... (8548)
Huddersfield... 7124... (7685)
Salford... 6121... (2920)
Widnes... 5896... (5958)
Wakefield... 4609... (7150)
London... 1136... (1991)