More than a small number, in my view. I agree with your earlier post that his output became more uneven after 1995, but then so did Morrissey's output in general. Certainly his contribution on Your Arsenal and Vauxhall is pretty much flawless:
Your Arsenal Glamorous Glue, We'll Let You Know, The National Front Disco, Certain People I Know, We Hate It When Our Friends Become Successful, You're the One for Me, Fatty, Seasick, Yet Still Docked, Tomorrow
Vauxhall and I Billy Budd, Hold On to Your Friends, Why Don't You Find Out for Yourself?, I Am Hated for Loving, Used to Be a Sweet Boy, The Lazy Sunbathers
And in the subsequent years he still managed a decent number of stand-out tracks - some of them sublime:
The Operation, Dagenham Dave, Southpaw, Alma Matters, Trouble Loves Me, Irish Blood, English Heart, I Have Forgiven Jesus, First of the Gang to Die, Let Me Kiss You, Dear God Please Help Me, Life Is a Pigsty, It's Not Your Birthday Anymore, Ganglord, The Never Played Symphonies, Let the Right One Slip In, Boxers, Sunny, A Swallow on My Neck, Have-a-Go Merchant, Nobody Loves Us, The Edges Are No Longer Parallel
Obviously opinions are subjective, but I just cannot get as excited by the more recent material. To me it lacks heart, spark, cohesiveness and most of all, good tunes. I sometimes think when Morrissey dispensed, bit by bit, with 'the lads', he lost a lot of the Englishness that his musical identity was built on; and having replaced them with Jesse, Mando and Gustavo - in what looks an awful lot like cynically pandering to his South American market - this disconnect seems ever greater. To me, flinging multiple world music influences at the wall to see what sticks has not served him well in this regard. I also can't help wondering if this at least partly explains the decline in his lyrics; it's as if even he's not connecting with his own music any more. Or perhaps he's just run out of things to say. Anyway, I agree with you that the covers album will be interesting.