Holdings gaps
[N=1990,7.3.,31.3.,16.-17.4.,31.5.,26.6.,3.7.,5.7.,20.7.,1.8.,29.9.,3.10.,17.10.-20.10.,26.-27.10.,24.11.,26.-27.11.,2.12.,6.12.,8.12.,15.12.,19.12.,21.-22.12; 1991,26.1.,7.3.,9.3.,11.3.,4.5.,15.6.,29.6.,20.7.,22.7.,26.8.,28.-30.8.,3.9.-7.9.,9.9.-14.9.,16.9.-21.9.,23.9.,26.9.,28.9.]