1989. Senate and part of the lower house have free elections, the majority of the lower house is reserved for the communists and their puppet parties. Result: candidates nominated by Solidarity sweep every single freely contested seat in the lower house, all except one in the Senate. Seeing the writing on the wall, enough communist and puppet party parliamentarians split off to give a majority to a unified Solidarity government.

1991. Solidarity by now splintering into numerous parties, which between them get most of the votes. Unstable governments as the parties bicker. Main division is between the old dissident movement and those who became prominent post 1980 and are generally more to the right.

1993. Most of the Solidarity parties disappear as the post communists and the peasant party win the elections.  The seat distribution is far more skewed than the vote as right wing parties get only a miniscule number of seats in spite of winning close to a third of the vote: 5%/8% threshold proves fatal to the splintered right. Main opposition is the old dissident party, the UW.

1997. The AWS, a cobbled together coalition of the right wing parties under the umbrella of Solidarity, wins a convincing victory and governs in coalition with the UW. Parties continually split off and by the last year of the parliament there is a very weak minority govt.

2001. The AWS and the UW both fail to get into parliament. The post communist SLD gets about 40% of the vote and about 50% of the seats. The two main opposition parties are the PO - the ultra-liberal right wing minority of the old UW with a few ultra liberals from the AWS and PiS, a bunch of AWS types under the aegis of the Kaczynski twins who had been the organizing genius behind the AWS but had split off almost immediately.

Now that is what I call instability - ruling parties disappearing completely or turning into sliver ones comparable in size to the FDP or Greens.  Even the new Laender have nothing to compare to that.