Thank you for you comment!

Our notions of "spiritual" are heavily dependent on our culture and socio-economic backgrounds.
I'm begging for some definitions; or minimally some constraints!

I'm sure these was based only on subjective reports of participants and were pretty different for each of them. You can find few questionnaires "measuring" spiritual/mystical experiences but they of course have nothing to do with spirituality per se - they only treat on psychological nature of this kind of experiences, not ontological.

Jesse and Griffiths used mostly Mystical Experience Questionnaire and Persisting Effects Questionnaire.