I believe the old generation is the only religious group in this country.
Not really, there are also young people in Poland who are very religious (and middle-aged people too). However, I remember reading a couple of CBOS reports which said that higher importance of religion was more likely to be found in older people, people who live in rural areas and people who have only primary level education.
Religious faith is important only for 12% of people there. It's very low!
Could you perhaps link to the source of this info? I'd like to see the questions for myself.
That figure isn't so low compared to other data from CBOS polls, e.g. back in 2007 when people had to pick a single thing about Christmas which gave them most joy, only 5% said the religious rituals give them most joy; 71% chose family gatherings as the best bit of Christmas; in 2011 fewer than three in ten Poles said that Christmas is primarily a religious holiday.