\begin{table}
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\par
\caption{Main observational properties of the dm radio spikes
shorter than 100~ms, observed between February 2000 and December
2001 with the 15-m radio telescope and fast radiospectrograph of
Toru\'n Observatory. The drifts in frequency were calculated for
spikes with inclined dynamic spectra only, vertical spectra were
considered as having non-measurable drifts.}\label{t1}
 {
\begin{tabular}{lrrrrrrrrrrr}
\hline\hline & \multicolumn{6}{c}{2000} \vline & \multicolumn{4}{c}{2001} \vline \\
\cline{2-12}        & 15 Mar.& 26 Mar.& 17 May& 21 May& 21 Jun.& 11 Jul.& 22 Mar.& 23 Apr.& 14 May& 30 Oct. & all\\
\hline
No. of spikes         & 854 & 208 & 73 & 143 & 629 & 1403 & 174 & 576 & 876 & 392 & 5328 \\
No. spikes $<$100~ms   & 817 & 156 & 62 & 143 & 597 & 1383 & 173 & 576& 876 & 382 & 5165 \\
Duration (s) &&&&&&&&&&\\
min/max & 0.015/0.099 & 0.025/0.099 & 0.029/0.099 & 0.010/0.046 & 0.012/0.099 &
0.009/0.099 & 0.008/0.099 & 0.003/0.071 & 0.004/0.051 & 0.005/0.099 & 0.003/0.099 \\
mean/median (skew.)  & 0.058/0.057 (0.2) & 0.064/0.064 (0.6) &
0.069/0.073 (-0.5) & 0.02/0.018 (1.4) & 0.046/0.041 (0.7) &
0.029/0.024 (1.9) & 0.037/0.032 (0.9) & 0.026/0.023 (0.8) &
0.015/0.013 (1.9) & 0.047/0.046 (0.333) & 0.036/0.029 (0.8) \\
Width (MHz): &&&&&&&&&&\\
min/max & 3.1/18.9 & 4.2/20.4  & 3.6/17.9  & 3.1/26.4  &
3.8/35.5  & 3.1/31.4 & 3.1/26.7 & 3.0/23.8 & 3.0/34.5 & 3.1/25.9 & 3.0/35.5 \\
mean/median (skew.)  & 8.19/7.9 (0.7) & 9.69/9.5 (0.8) & 9.96/9.8
(0.3) & 10.07/9.2 (1.3) & 11.36/10.6 (1.2) &10.43/9.5 (1.0) &
10.19/9.5 (0.9) & 8.47/8.2 (0.8) & 9.97/9.0 (1.2) &
12.30/12.0 (0.2) & 10.0/9.2 (1.1) \\
Relative width (\%) &&&&&&&&&&\\
min/max                & 0.21/1.31 & 0.29/1.40 & 0.25/1.23 &
0.23/1.92 & 0.27/2.47 & 0.21/2.42 & 0.22/1.88 & 0.21/1.65 & 0.21/2.42 & 0.22/1.82 & 0.21/2.47 \\
mean/median (skew.)  & 0.58/0.56 (0.7) & 0.68/0.66 (0.7) &
0.70/0.67 (0.4) & 0.72/0.66 (1.3) & 0.80/0.74 (1.1) & 0.74/0.68
(1.0) & 0.72/0.69 (0.8) & 0.60/0.58 (0.8) & 0.70/0.64
(1.2) & 0.87/0.86 (0.2) & 0.70/0.65 (1.1) \\
Negative drifts (MHz/s) &&&&&&&&&&\\
No. spikes  &642 & 140 & 49 & 49 & 437 & 212 & 122 & 430 & 253 & 344 & 2678 \\
min/max & 63/2630 & 92/1798 & 124/1007 & 261/5462 & 86/4976 &
64/3850 & 196/2595 & 69/12141 & 215/13569 & 113/5491 & 63/13569 \\
mean/median (skew.) & 396/312 (2.7) & 307/239 (3.9) & 301/206
(2.0) & 1920/1484 (0.9) & 630/501 (3.1) & 1170/992 (0.7) &
616/539 (2.6) & 596/316 (6.4) & 2607/2257 (2.1) & 462/347 (6.9) & 776/405 (4.4) \\
Positive drifts (MHz/s) &&&&&&&&&&\\
no. spikes & 85 & 8 & 7 & 40 & 105 & 179 & 17 & 24 & 221 & 20 & 706 \\
min/max      & 51/2444 & 218/872 & 87/1971 & 250/9102 &
116/2788 & 143/5155 & 111/1771 & 117/13425 & 242/9525 & 236/3624 & 51/13425 \\
mean/median (skew.)  & 688/544 (1.5) & 462/384 (0.5) & 632/433
(1.3) & 2837/2443 (1.1) & 815/580 (1.5) & 1219/1055 (1.3)
& 761/637 (0.3) & 1752/719 (3.0) & 2607/2415 (1.2) & 1157/1195 (1.1) & 1612/1105 (2.3) \\
\hline
\end{tabular}}
\end{table}