How long is a piece of 5 twine string on it's own and once you start to separate the individual strands of twine ?
LBGTQ you say
well that's broad. Most stuff i watch is just G - i avoid L and T bores me - Q is a bit on and off
How much G you say needs to occur to make it counts as G ?
Well a no messing attitude would say can we cut to the chase and get to the gay. However there's loads of stuff where the gay brews slowly and hits abut half way - the coming out genre often has this. There's also the is he / isnt he for example The talented Mr Ripley which takes time to become specifically gay whilst building obvious subtle homoerotic tension.
There are films and tv dramas where the gay character/s sit in among a whole cast of straights and that works too - tho the actual % portioned to the gay sub-plot might only be in total 20-25%. So the gay narrative may have a bigger dramatic impact but less air time. Take some of the new movies - like weekend - pushing boundaries by showing graphic gay sex whilst not in other ways being particularly gay. So even one of the genres , like gay has a hugely broad application.
Then the Queer and camp genres. So the camp genre may not have any specific gay refs but be exceedingly gay or camp - for example the Carrie Fisher documentary 'Wishful Drinking' is as camp as Christmas and gay-icon friendly but nothing gay actually referred too. Alot of old movies and tv series can have that quality too.
Then take a film like ' A single Man' its all gay gay gay but actually what it's really about is nothing to do with gay. It's really about despair.
So the more you answer your question the less it makes sense. A film is not best quantified in terms of singular %s. That's an absurdist measure.
A subject or genre isn't necessarily going to follow expectations and be formulaic. The term 'gay themed' isn't really an exact quantum. It's a general guide which is loose and problematic and subject to different meaning. Mostly it serves to signpost an audience towards representations and depictions of themselves in a world where they often feel excluded or under represented. For me the answer to your question isnt how much, but how well has a film accommodated my needs. That usually means in some sense or another i feel a subtle but rewarding sense that the characters i'm being asked to get involved with reflect back something of myself however different the reality they inhabit may be from my own. Without that sense of connection i quickly loose interest. That's about representation not quantity. To add there are plenty of gay films where i just think this is rubbish and im not interested in the characters because the acting is bad or the script crap and that can break the success of the vital connection i need.
There's a film buff torrent website called Karagarga which often debates if to create a film category of LBGTQ and more often they decide against it. They do have a queer film collection section but no main-page LBGTQ category. What they call queer is very broad and includes all kinds of artist's video work and abstract work by queer artists. Some of us, like me do argue from time to time that a LBGTQ catagory in some sense should exist. But even then i believe that L,B,G,T are somewhat lumped together when in reality they often have little in common with each other in terms of the requirements of the character's journey. I'm not sure i think L does really belong alongside G except in terms of being a minority which is oppressed and controlled by the same social institutions. But do you lump minority migrant populations like Chinese and Jamaican together just because they share the same pressures as a minority ?