Sample time-series histogram buckets

gistfile1.txt

+------------+--------+-----+
| date       | bucket | cnt |
+------------+--------+-----+
| 2012-07-20 |    800 | 119 | 
| 2012-07-20 |    900 | 123 | 
| 2012-07-20 |   1000 | 173 | 
| 2012-07-20 |   1100 | 226 | 
| 2012-07-20 |   1200 | 284 | 
| 2012-07-20 |   1300 | 257 | 
| 2012-07-20 |   1400 | 268 | 
| 2012-07-20 |   1500 | 244 | 
| 2012-07-20 |   1600 | 191 | 
| 2012-07-20 |   1700 | 204 | 
| 2012-07-20 |   1800 | 187 | 
| 2012-07-20 |   1900 | 177 | 
| 2012-07-20 |   2000 | 164 | 
| 2012-07-20 |   2100 | 125 | 
| 2012-07-20 |   2200 | 140 | 
| 2012-07-20 |   2300 | 109 | 
| 2012-07-20 |   2400 | 103 | 
| 2012-07-21 |    800 | 123 | 
| 2012-07-21 |    900 | 165 | 
| 2012-07-21 |   1000 | 237 | 
| 2012-07-21 |   1100 | 278 | 
| 2012-07-21 |   1200 | 338 | 
| 2012-07-21 |   1300 | 306 | 
| 2012-07-21 |   1400 | 316 | 
| 2012-07-21 |   1500 | 269 | 
| 2012-07-21 |   1600 | 271 | 
| 2012-07-21 |   1700 | 241 | 
| 2012-07-21 |   1800 | 188 | 
| 2012-07-21 |   1900 | 174 | 
| 2012-07-21 |   2000 | 158 | 
| 2012-07-21 |   2100 | 153 | 
| 2012-07-21 |   2200 | 132 | 
| 2012-07-22 |    900 | 154 | 
| 2012-07-22 |   1000 | 241 | 
| 2012-07-22 |   1100 | 246 | 
| 2012-07-22 |   1200 | 300 | 
| 2012-07-22 |   1300 | 305 | 
| 2012-07-22 |   1400 | 301 | 
| 2012-07-22 |   1500 | 292 | 
| 2012-07-22 |   1600 | 253 | 
| 2012-07-22 |   1700 | 251 | 
| 2012-07-22 |   1800 | 214 | 
| 2012-07-22 |   1900 | 189 | 
| 2012-07-22 |   2000 | 179 | 
| 2012-07-22 |   2100 | 159 | 
| 2012-07-22 |   2200 | 161 | 
| 2012-07-22 |   2300 | 144 | 
| 2012-07-22 |   2400 | 139 | 
| 2012-07-22 |   2500 | 132 | 
| 2012-07-22 |   2600 | 136 | 
| 2012-07-22 |   2800 | 105 | 
| 2012-07-23 |    800 | 120 | 
| 2012-07-23 |    900 | 156 | 
| 2012-07-23 |   1000 | 209 | 
| 2012-07-23 |   1100 | 267 | 
| 2012-07-23 |   1200 | 299 | 
| 2012-07-23 |   1300 | 316 | 
| 2012-07-23 |   1400 | 318 | 
| 2012-07-23 |   1500 | 307 | 
| 2012-07-23 |   1600 | 295 | 
| 2012-07-23 |   1700 | 273 | 
| 2012-07-23 |   1800 | 283 | 
| 2012-07-23 |   1900 | 229 | 
| 2012-07-23 |   2000 | 192 | 
| 2012-07-23 |   2100 | 193 | 
| 2012-07-23 |   2200 | 170 | 
| 2012-07-23 |   2300 | 164 | 
| 2012-07-23 |   2400 | 154 | 
| 2012-07-23 |   2500 | 138 | 
| 2012-07-23 |   2600 | 101 | 
| 2012-07-23 |   2700 | 115 | 
| 2012-07-23 |   2800 | 103 | 
| 2012-07-24 |    800 | 105 | 
| 2012-07-24 |    900 | 156 | 
| 2012-07-24 |   1000 | 220 | 
| 2012-07-24 |   1100 | 255 | 
| 2012-07-24 |   1200 | 308 | 
| 2012-07-24 |   1300 | 338 | 
| 2012-07-24 |   1400 | 318 | 
| 2012-07-24 |   1500 | 255 | 
| 2012-07-24 |   1600 | 278 | 
| 2012-07-24 |   1700 | 260 | 
| 2012-07-24 |   1800 | 235 | 
| 2012-07-24 |   1900 | 230 | 
| 2012-07-24 |   2000 | 185 | 
| 2012-07-24 |   2100 | 145 | 
| 2012-07-24 |   2200 | 147 | 
| 2012-07-24 |   2300 | 157 | 
| 2012-07-24 |   2400 | 109 | 
| 2012-07-25 |    800 | 104 | 
| 2012-07-25 |    900 | 191 | 
| 2012-07-25 |   1000 | 201 | 
| 2012-07-25 |   1100 | 238 | 
| 2012-07-25 |   1200 | 223 | 
| 2012-07-25 |   1300 | 229 | 
| 2012-07-25 |   1400 | 286 | 
| 2012-07-25 |   1500 | 256 | 
| 2012-07-25 |   1600 | 240 | 
| 2012-07-25 |   1700 | 233 | 
| 2012-07-25 |   1800 | 202 | 
| 2012-07-25 |   1900 | 180 | 
| 2012-07-25 |   2000 | 184 | 
| 2012-07-25 |   2100 | 161 | 
| 2012-07-25 |   2200 | 125 | 
| 2012-07-25 |   2300 | 110 | 
| 2012-07-25 |   2400 | 101 | 
| 2012-07-26 |   1300 | 132 | 
| 2012-07-26 |   1400 | 117 | 
| 2012-07-26 |   1500 | 124 | 
| 2012-07-26 |   1600 | 154 | 
| 2012-07-26 |   1700 | 167 | 
| 2012-07-26 |   1800 | 137 | 
| 2012-07-26 |   1900 | 169 | 
| 2012-07-26 |   2000 | 175 | 
| 2012-07-26 |   2100 | 168 | 
| 2012-07-26 |   2200 | 188 | 
| 2012-07-26 |   2300 | 137 | 
| 2012-07-26 |   2400 | 173 | 
| 2012-07-26 |   2500 | 164 | 
| 2012-07-26 |   2600 | 167 | 
| 2012-07-26 |   2700 | 115 | 
| 2012-07-26 |   2800 | 116 | 
| 2012-07-26 |   2900 | 118 | 
| 2012-07-26 |   3000 | 125 | 
| 2012-07-26 |   3200 | 104 | 
+------------+--------+-----+